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A241031
Sum of n-th powers of divisors of 28.
2
6, 56, 1050, 25112, 655746, 17766056, 489541650, 13599182072, 379283617986, 10599157616456, 296486304875250, 8297561014164632, 232274972859656226, 6502905234227329256, 182070232515259616850, 5097810928082584052792
OFFSET
0,1
LINKS
Index entries for linear recurrences with constant coefficients, signature (56,-1043,8240,-29204,43904,-21952).
FORMULA
G.f.: 2*(3 - 140*x + 2086*x^2 - 12360*x^3 + 29204*x^4 - 21952*x^5)/((1 - x)*(1 - 2*x)*(1 - 4*x)*(1 - 7*x)*(1 - 14*x)*(1 - 28*x)).
a(n) = (4^n + 2^n + 1)*(7^n + 1).
MATHEMATICA
Total[#^Range[0, 20] & /@ Divisors[28]] (* or *) Table[(4^n + 2^n + 1) (7^n + 1), {n, 0, 20}]
PROG
(Magma) [DivisorSigma(n, 28): n in [0..20]]; /* or */ [(4^n+2^n+1)*(7^n+1): n in [0..20]];
CROSSREFS
Cf. A018254 (divisors of 28).
Cf. similar sequence listed in A241029.
Sequence in context: A052317 A185524 A122743 * A268760 A137032 A053421
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 17 2014
STATUS
approved