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A126192
Product of the even divisors of 2n.
5
2, 8, 12, 64, 20, 576, 28, 1024, 216, 1600, 44, 110592, 52, 3136, 3600, 32768, 68, 373248, 76, 512000, 7056, 7744, 92, 84934656, 1000, 10816, 11664, 1404928, 116, 207360000, 124, 2097152, 17424, 18496, 19600, 5159780352, 148, 23104, 24336, 655360000, 164
OFFSET
1,1
LINKS
FORMULA
a(n) = 2^A000005(n) * A007955(n). - Robert Israel, Feb 01 2019
MAPLE
seq(mul(2*t, t=numtheory:-divisors(n)), n=1..100); # Robert Israel, Feb 01 2019
MATHEMATICA
Table[Times@@Select[Divisors[2n], EvenQ], {n, 50}] (* Harvey P. Dale, Jul 19 2011 *)
a[n_] := 2^(d = DivisorSigma[0, n]) * n^(d/2); Array[a, 100] (* Amiram Eldar, Jun 26 2022 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jul 14 2008
STATUS
approved