A139117 Triangular numbers (A000217) with indices A000043.

3, 6, 15, 28, 91, 153, 190, 496, 1891, 4005, 5778, 8128, 135981, 184528, 818560, 2427706, 2602621, 5176153, 9046131, 9783676, 46943205, 49416711, 62871291, 198751953, 235477551, 269340445, 990013753, 3718970646, 6105511756, 8718535225, 23347768186, 286403014380

Offset

1,1

Links

Table of n, a(n) for n=1..32.

Formula

a(n) = A000217(A000043(n)).

Example

a(4) = 28 because A000043(4) = 7 and the 7th triangular number A000217(7) is 28.

Crossrefs

Cf. A000217, A000396, A034953.

Sequence in context: A034953 A086737 A063834 * A226736 A066708 A034464

Adjacent sequences: A139114 A139115 A139116 * A139118 A139119 A139120

Keyword

nonn

Author

Omar E. Pol, May 08 2008

Status

approved