A073872 Smallest positive triangular number not included earlier that is a multiple of n (a permutation of the triangular numbers).

1, 6, 3, 28, 10, 36, 21, 120, 45, 190, 55, 276, 78, 210, 15, 496, 136, 378, 171, 300, 105, 66, 253, 528, 325, 780, 351, 1176, 406, 630, 465, 2016, 231, 1326, 595, 2556, 666, 1596, 741, 2080, 820, 3486, 903, 1540, 990, 2346, 1081, 4560, 1225, 2850, 153, 5356

Offset

1,2

Links

Table of n, a(n) for n=1..52.

Mathematica

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]]]]

Crossrefs

Cf. A073873, A073874.

Sequence in context: A287546 A285559 A066561 * A281677 A282303 A286166

Adjacent sequences: A073869 A073870 A073871 * A073873 A073874 A073875

Keyword

nonn

Author

Amarnath Murthy, Aug 16 2002

Extensions

Edited by Dean Hickerson, Oct 15 2002

Status

approved