|
%I #9 Feb 03 2015 19:21:57
%S 1,3,3,3,2,3,5,11,9,7,4,3,9,7,12,11,6,27,13,27,12,4,8,27,17,35,27,19,
%T 10,12,21,43,15,23,5,27,25,19,9,27,14,12,29,11,27,8,16,75,33,67,6,35,
%U 18,27,15,75,51,39,20,27,41,31,54,43,22,15,45,40,54,7,24,27,49,99,42,19,26,39
%N Smallest m such that n divides the pentagonal number A000326(m).
%H Harvey P. Dale, <a href="/A085767/b085767.txt">Table of n, a(n) for n = 1..1000</a>
%e Let pe(m)=m*(3m-1)/2. The pe(1)=1, pe(2)=5, pe(3)=12. As pe(3) is the first divisible by 6, a(6)=3.
%t smn[n_]:=Module[{m=1,c},c=(m(3m-1))/2;While[!Divisible[c,n],m++;c=(m(3m-1))/2];m]; Array[smn, 80] (* _Harvey P. Dale_, Feb 03 2015 *)
%o (PARI) pe(n)=n*(3*n-1)/2 for (n=1,50,c=1; while (pe(c)%n!=0,c++); print1(c","))
%Y Cf. A011772 (triangular numbers), A019554 (squares).
%K nonn
%O 1,2
%A _Jon Perry_, Jul 22 2003
%E More terms from _David Wasserman_, Feb 10 2005
|
