OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..1660
T. Pisanski, D. Schattschneider and B. Servatius, Applying Burnside's lemma to a one-dimensional Escher problem, Math. Mag., 79 (2006), 167-180. See V(n).
FORMULA
a(n) = n * A001868(n).
a(n) = Sum_{k=1..n} 4^gcd(n,k). - Ilya Gutkovskiy, Apr 16 2021
MAPLE
A054611:=proc(n) local k, t1; t1:=0; for k in divisors(n) do t1 := t1+phi(k)*4^(n/k); od: t1; end;
PROG
(PARI) a(n) = if(n==0, 0, sumdiv(n, d, eulerphi(d)*4^(n/d))); \\ Michel Marcus, Sep 19 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Apr 16 2000
STATUS
approved