This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
default(primelimit, 2^30); A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)}; A064216(n) = A064989((2*n)-1); A254103(n) = { if(0==n,0,if(!(n%2),(3*A254103(n/2))-1,(3*(1+A254103((n-1)/2)))\2)); }; A254116(n) = A064216(A254103(n)); for(n=1, 8192, write("b254116.txt", n, " ", A254116(n)));
from sympy import factorint, prevprime, floor
from operator import mul
def a064216(n):
f=factorint(2*n - 1)
return 1 if n==1 else reduce(mul, [prevprime(i)**f[i] for i in f])
def a254103(n):
if n==0: return 0
if n%2==0: return 3*a254103(n/2) - 1
else: return floor((3*(1 + a254103((n - 1)/2)))/2)
def a(n): return a064216(a254103(n)) # Indranil Ghosh, Jun 06 2017
(define (A254116 n) (A064216 (A254103 n)))
from sympy import factorint, nextprime
from operator import mul
def a048673(n):
f = factorint(n)
return 1 if n==1 else (1 + reduce(mul, [nextprime(i)**f[i] for i in f]))/2
def a254104(n):
if n==0: return 0
if n%3==0: return 1 + 2*a254104(2*n/3 - 1)
elif n%3==1: return 1 + 2*a254104(2*(n - 1)/3)
else: return 2*a254104((n - 2)/3 + 1)
def a254115(n): return a254104(a048673(n))
def a(n): return (a254115(2*n + 1) - 1)/2 # Indranil Ghosh, Jun 06 2017