%I #10 Jun 09 2017 10:49:00
%S 1,2,6,4,4,5,10,6,8,4,8,12,4,4,24,16,4,8,8,8,12,4,16,24,6,4,20,8,4,18,
%T 12,10,12,4,16,16,8,8,36,12,4,16,8,16,16,4,12,24,9,12,32,8,4,10,32,12,
%U 12,8,8,40,4,4,48,12,16,12,8,8,16,8,20,48,4,4
%N Number of divisors of the n-th heptagonal number.
%H Colin Barker, <a href="/A276680/b276680.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = A000005(A000566(n)).
%e a(3) = 6 because the 3rd heptagonal number is 18, which has 6 divisors: 1,2,3,6,9,18.
%t DivisorSigma[0,PolygonalNumber[7,Range[80]]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jun 09 2017 *)
%o (PARI)
%o pg(m, n) = (n^2*(m-2)-n*(m-4))/2 \\ n-th m-gonal number
%o vector(100, n, numdiv(pg(7,n)))
%Y Cf. A000005, A000566.
%Y Cf. A063440 (m=3), A048691 (m=4), A276678 (m=5), A276679 (m=6), A276681 (m=8), A276682 (m=9), A276683 (m=10).
%K nonn
%O 1,2
%A _Colin Barker_, Sep 13 2016