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 A054611 a(n) = Sum_{d|n} phi(d)*4^(n/d). 4
 0, 4, 20, 72, 280, 1040, 4200, 16408, 65840, 262296, 1049680, 4194344, 16782000, 67108912, 268451960, 1073744160, 4295033440, 17179869248, 68719747320, 274877907016, 1099512679520, 4398046544304, 17592190238920, 70368744177752 (list; graph; refs; listen; history; text; internal format)
 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). 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 Column k=4 of A185651. Sequence in context: A303011 A197426 A061981 * A196432 A302815 A196508 Adjacent sequences:  A054608 A054609 A054610 * A054612 A054613 A054614 KEYWORD nonn AUTHOR N. J. A. Sloane, Apr 16 2000 STATUS approved

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Last modified October 21 19:27 EDT 2019. Contains 328312 sequences. (Running on oeis4.)