A129514
a(n) = gcd(Sum_{k|n} k, Sum_{1A000203(n).
1, 3, 2, 1, 3, 3, 4, 3, 1, 1, 6, 2, 7, 3, 24, 1, 9, 3, 10, 42, 1, 1, 12, 60, 1, 3, 2, 14, 15, 3, 16, 3, 3, 1, 6, 1, 19, 3, 4, 10, 21, 3, 22, 6, 3, 1, 24, 4, 1, 3, 6, 2, 27, 15, 4, 12, 1, 1, 30, 6, 31, 3, 8, 1, 3, 3, 34, 6, 3, 1, 36, 3, 37, 3, 2, 14, 3, 3, 40, 6
Offset: 1
Keywords
Programs
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Maple
A129514 := proc(n) gcd( numtheory[sigma](n),n*(n+1)/2) ; end: seq(A129514(n),n=1..80) ; # R. J. Mathar, Oct 30 2007
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Mathematica
nterms=100;Table[GCD[DivisorSigma[1,n],PolygonalNumber[n]],{n, nterms}] (* Paolo Xausa, Nov 27 2021 *)
Formula
Extensions
More terms from R. J. Mathar, Oct 30 2007
Comments