autopushed

First I calculated hex(11) in my head, took about half an hour.

Then I tried to make sense of the sequence the best I could before
looking up the closed form.

bin/hex.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+# https://click.palletsprojects.com/en/8.1.x/arguments/
+# https://click.palletsprojects.com/en/8.1.x/options/
+
+import click
+import math
+import sys
+
+# I'm not proud (I am a little bit?).
+PROOF = [] # :)
+
+class AgoraCmd(click.Command):
+    def format_help(self, ctx, formatter):
+        click.echo("""Usage:
+        - Visit anagora.org/primes to execute this file in the Agora of Flancia.
+        - Visit e.g. anagora.org/primes/17 to test if 17 is prime.
+        - In general visit anagora.org/foo, anagora.org/foo/bar to execute e.g. <bin/foo.py bar> from your garden.
+        """)
+
+    def __call__(self, *args, **kwargs):
+        try:
+            return super(AgoraCmd, self).__call__(
+                *args, standalone_mode=False, **kwargs)
+        except click.MissingParameter as exc:
+            exc.ctx = None
+            exc.show(file=sys.stdout)
+            click.echo()
+            try:
+                super(AgoraCmd, self).__call__(['--help'])
+            except SystemExit:
+                sys.exit(exc.exit_code)
+
+@click.command(cls=AgoraCmd)
+@click.argument('n', type=click.INT)
+def hexnum(n, centered=True):
+    """Calculates the first n hex numbers just for fun :)"""
+
+    # Going through this from first principles (from memory/deducing this) for fun :) 
+
+    # Why does the first list comprehension I wrote knowing it was wrong not work? 
+    # Is it because of its complexity? Note I don't know the 'closed form' for hex numbers yet but I think it exists.
+    # To calculate them, I only know you need to add 6 more than after the previous number. 
+    # But that can't be (trivially) expressed in a list comprehension.
+    # 
+    # hexnums = [int(centered) + 6*n for n in range(0,n)]
+    # click.echo(f"These are not all hex numbers, but some are: {list(enumerate(hexnums))}")
+
+    # If we could skip one, then two, then three from the list above, 
+    # we could exclude all non-hex-numbers.
+    # is there something in itertools that can do this for us?
+    # I don't think so. Maybe dropwhile with the right lambda?
+
+    # ...anyway, going at it old school.
+    # acc = int(centered)
+    # for row in range(0, n+1):
+    #     acc += 6 * row
+    #     click.echo(f"hex({row}) is {acc}.")
+
+    # ...and then https://oeis.org/A003215 to the rescue :)
+    # [[crystal ball sequence for hexagonal lattice]]: why does this work?
+    # -> https://en.wikipedia.org/wiki/Centered_hexagonal_number
+    # It is a cubic polynomial and Wikipedia shows how to convince yourself that it works. 
+    # Beautiful :)
+    hexnums = [3*n*(n+1)+1 for n in range(0,n+1)]
+
+    for nth, hexnum in enumerate(hexnums):
+        click.echo(f"hex({nth}) is {hexnum}.")
+
+
+if __name__ == '__main__':
+    hexnum()

bin/prime.py

@@ -18,7 +18,7 @@ def print_sieve(sieve):
     primes = []
     for n, prime in enumerate(sieve):
         if n >= 2 and prime:
-            primes.append('[[' + str(n) + ']]')
+            primes.append(str(n))
     return ", ".join(primes)
 
 def is_prime(n):
@@ -73,9 +73,9 @@ def prime(n):
     """Simple program that factors a number using a [[Sieve of Eratosthenes]]."""
     p, sieve = is_prime(n)
     if p:
-        click.echo(f"**{n}** is **prime**.")
+        click.echo(f"[[{n}]] is *prime*.")
     else:
-        click.echo(f"**{n}** is **not prime**. Want proof? :)")
+        click.echo(f"[[{n}]] is *not prime*. Want proof? :)")
         click.echo("\n".join([line for line in PROOF if f'[[{n}]]' in line]))
 
     click.echo(f"\nPrimes up to {n}: {print_sieve(sieve)}.")

journal/2023-10-17.md

@@ -4,3 +4,12 @@
     - I checked with the [[dentist]] and they didn't mind (I tested negative for Covid yesterday), so I went ahead and I'm happy with the results!
   - [[Agora]]!
     - I thought of implementing ! as a short for #push, meaning that anything wikilinked and "strongly asserted" behaves the same as push: the following blocks are transcluded in the destination.
+    - [[open letters]]!
+      - [[open letter to musk]]
+      - [[carta abierta a milei]]
+    - [[hex]] numbers :)
+    - I calculated [[397]] as the 11th hex number, but if you define them naturally (with one ball yielding the first hex number, not the zeroeth) it would be [[469]]
+      - Still it was fun to do it in my head :) it took 15'-25' while I was doing yoga.
+      - I came away with a renewed appreciation of hex numbers.
+    - I then decided to code an hex [[number]] producer :)
+      - https://github.com/flancian/garden/commit/3d4e608b6cb78aa55b039cd6ce0716e9d8275e9d just for fun.

open letter to musk.md

@@ -0,0 +1,3 @@
+- an [[open letter]].
+  - #go https://docs.google.com/document/d/1RpO8zn2DbG6_pUiLmtk6aoJawZV3UA_cz8Z57jMEubg/edit
+  - #pull [[open letter to elon musk]]