A075349 a(1) = 1; first differences follow the pattern 1,2,2,3,3,3,4,4,4,4,5,5,5,5,5,..., i.e., the next n differences are n.

1, 2, 4, 6, 9, 12, 15, 19, 23, 27, 31, 36, 41, 46, 51, 56, 62, 68, 74, 80, 86, 92, 99, 106, 113, 120, 127, 134, 141, 149, 157, 165, 173, 181, 189, 197, 205, 214, 223, 232, 241, 250, 259, 268, 277, 286, 296, 306, 316, 326, 336, 346, 356, 366, 376, 386, 397, 408

Offset: 1

Author

Amarnath Murthy, Sep 19 2002

Keywords

• nonn

Links

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

Programs

Mathematica

Accumulate[Join[{1},Flatten[Table[Table[n,{n}],{n,12}]]]] (* Harvey P. Dale, Aug 26 2013 *)

Formula

a(n) = A060432(n-1) + 1. - David Wasserman, Jan 16 2005

Extensions

More terms from David Wasserman, Jan 16 2005