A081491 Triangle read by rows in which the n-th row contains n terms of an arithmetic progression with a common difference of (n-1) and the first term of (n+1)-th row is 1 more than the last term of the n-th row.

1, 2, 3, 4, 6, 8, 9, 12, 15, 18, 19, 23, 27, 31, 35, 36, 41, 46, 51, 56, 61, 62, 68, 74, 80, 86, 92, 98, 99, 106, 113, 120, 127, 134, 141, 148, 149, 157, 165, 173, 181, 189, 197, 205, 213, 214, 223, 232, 241, 250, 259, 268, 277, 286, 295, 296, 306, 316, 326, 336, 346

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Example

1; 2,3; 4,6,8; 9,12,15,18; 19,23,27,31,35; 36,41,46,51,56,61; ...

Mathematica

Table[NestList[#+n-1&, (2n^3-9n^2+19n-6)/6, n-1], {n, 11}]//Flatten (* Harvey P. Dale, Feb 12 2024 *)

Crossrefs

Cf. A002522, A005408, A081489, A081490, A081492.

Sequence in context: A261342 A002348 A019469 * A048716 A010434 A074230

Adjacent sequences: A081488 A081489 A081490 * A081492 A081493 A081494

Keyword

nonn,tabl

Author

Amarnath Murthy, Mar 25 2003

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 29 2003

Status

approved