A076972 a(n) = index of the triangular number A076971(n).

1, 2, 3, 5, 7, 10, 15, 21, 30, 43, 61, 87, 123, 174, 247, 349, 494, 699, 989, 1399, 1979, 2799, 3959, 5599, 7919, 11199, 15838, 22399, 31677, 44799, 63355, 89598, 126711, 179197, 253423, 358395, 506847, 716790, 1013695, 1433581, 2027390, 2867163

Offset

1,2

Links

Table of n, a(n) for n=1..42.

Crossrefs

Cf. A076971.

Sequence in context: A238543 A184641 A225490 * A301756 A170877 A003410

Adjacent sequences: A076969 A076970 A076971 * A076973 A076974 A076975

Keyword

nonn

Author

Amarnath Murthy, Oct 21 2002

Extensions

Corrected and extended by Sascha Kurz, Jan 22 2003

Status

approved