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A034662 Sum of n-th powers of divisors of 20. 3
6, 42, 546, 9198, 170898, 3304182, 65019786, 1290094638, 25700456418, 513002215782, 10250010815226, 204900053024478, 4097000260921938, 81930001287820182, 1638500006371967466, 32769000031591352718, 655370000156882923458 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

T. D. Noe, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (42,-609,3948,-12180,16800,-8000).

FORMULA

a(n) = (1 + 2^n + 4^n)*(1 + 5^n). - Bruno Berselli, Apr 17 2014

G.f.: -6*(2800*x^5 -4060*x^4 +1974*x^3 -406*x^2 +35*x -1) / ((x -1)*(2*x -1)*(4*x -1)*(5*x -1)*(10*x -1)*(20*x -1)). - Colin Barker, Apr 20 2014

MATHEMATICA

Total[#^Range[0, 20]&/@Divisors[20]] (* Vincenzo Librandi, Apr 17 2014 *)

Table[(1 + 2^n + 4^n) (1 + 5^n), {n, 0, 20}] (* Bruno Berselli, Apr 17 2014 *)

PROG

(Sage) [sigma(20, n) for n in xrange(0, 16)] # Zerinvary Lajos, Jun 04 2009

(MAGMA) [DivisorSigma(n, 20): n in [0..20]]; // Vincenzo Librandi, Apr 17 2014

CROSSREFS

Sequence in context: A254529 A098461 A284161 * A074651 A273922 A139223

Adjacent sequences:  A034659 A034660 A034661 * A034663 A034664 A034665

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified November 14 17:47 EST 2019. Contains 329126 sequences. (Running on oeis4.)