A076550 Indices of triangular numbers listed in A075088.

1, 2, 3, 7, 8, 15, 32, 64, 63, 224, 255, 1280, 512, 3968, 6399, 10240, 4095, 14336, 32768, 65535, 229375, 180224, 483327, 262143, 2097151, 1048575, 14680064, 17432576, 33554432, 67108864, 16777215

Offset

0,2

Comments

a(32) = 134217728. - Robert G. Wilson v, Jun 28 2010

Links

Donovan Johnson, Table of n, a(n) for n = 0..51

Formula

A000217(a(n)) = A075088(n).

Mathematica

f[n_] := Plus @@ Last /@ FactorInteger@n; t = Table[0, {100}]; k = 1; While[k < 10^9/4, a = f[k] + f[k + 1] -1; If[ t[[a + 1]] == 0, t[[a + 1]] = k; Print[{a, k}]]; k++ ]; t (* Robert G. Wilson v, Jun 28 2010 *)

Crossrefs

Cf. A000217, A075088.

Sequence in context: A097095 A101755 A363847 * A062269 A244508 A060121

Adjacent sequences: A076547 A076548 A076549 * A076551 A076552 A076553

Keyword

nonn

Author

Shyam Sunder Gupta, Oct 19 2002

Extensions

Edited by Ray Chandler, Dec 17 2004

a(26)-a(30) from Ray Chandler, Dec 22 2004

Status

approved