A073872 - OEIS

%I #7 Jun 24 2014 01:08:25

%S 1,6,3,28,10,36,21,120,45,190,55,276,78,210,15,496,136,378,171,300,

%T 105,66,253,528,325,780,351,1176,406,630,465,2016,231,1326,595,2556,

%U 666,1596,741,2080,820,3486,903,1540,990,2346,1081,4560,1225,2850,153,5356

%N Smallest positive triangular number not included earlier that is a multiple of n (a permutation of the triangular numbers).

%t a[n_] := a[n]=Module[{s, k, t}, s=a/@Range[1, n-1]; For[k=t=1, True, t+=++k, If[Mod[t, n]==0&&!MemberQ[s, t], Return[t]]]]

%Y Cf. A073873, A073874.

%K nonn

%O 1,2

%A _Amarnath Murthy_, Aug 16 2002

%E Edited by _Dean Hickerson_, Oct 15 2002