A034674 Sum of n-th powers of divisors of 128.
8, 255, 21845, 2396745, 286331153, 35468117025, 4467856773185, 567382630219905, 72340172838076673, 9241421688590303745, 1181745669222511412225, 151189550474521284184065, 19347536633519984760328193
Offset: 0
Links
- T. D. Noe, Table of n, a(n) for n=0..200
- Quynh Nguyen, Jean Pedersen, and Hien T. Vu, New Integer Sequences Arising From 3-Period Folding Numbers, Vol. 19 (2016), Article 16.3.1. Cites this sequence.
Programs
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Magma
[DivisorSigma(n, 128): n in [0..20]]; // Vincenzo Librandi, Apr 17 2014
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Mathematica
Total[#^Range[0, 20]&/@Divisors[128]] (* Vincenzo Librandi, Apr 17 2014 *)
Formula
a(n) = (2^(8*n) - 1)/(2^n - 1). Exp( Sum_{n >= 1} a(n)*x^n/n ) = 1 + 255*x + 43435*x^2 + ... is the o.g.f. for the 7th subdiagonal of triangle A022166, essentially A022190. - Peter Bala, Apr 07 2015