cp's OEIS Frontend

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.

A104258 Replace 2^i with n^i in binary representation of n.

Original entry on oeis.org

1, 2, 4, 16, 26, 42, 57, 512, 730, 1010, 1343, 1872, 2367, 2954, 3616, 65536, 83522, 104994, 130341, 160400, 194923, 234762, 280394, 345600, 406251, 474578, 551152, 637392, 732512, 837930, 954305, 33554432, 39135394, 45435458
Offset: 1

Views

Author

Ralf Stephan, Mar 05 2005

Keywords

Comments

The following sequences all appear to have the same parity: A003071, A029886, A061297, A092524, A093431, A102393, A104258, A122248, A128975. - Jeremy Gardiner, Dec 28 2008

Crossrefs

Cf. A104257.

Programs

  • PARI
    a(n) = my(b=binary(n)); sum(k=1, #b, b[k]*n^(#b-k)); \\ Michel Marcus, Mar 19 2015
    
  • Python
    def a(n): return sum(n**i*int(bi) for i, bi in enumerate(bin(n)[2:][::-1]))
    print([a(n) for n in range(1, 35)]) # Michael S. Branicky, Aug 02 2022

Formula

a(n) = A104257(n, n).
a(n) = [x^n] (1/(1 - x)) * Sum_{k>=0} n^k*x^(2^k)/(1 + x^(2^k)). - Ilya Gutkovskiy, Aug 17 2019