A138528 a(1) = 1. The n-th run (after the initial 1) of A138529(n) terms is (1,2,3,...,A138529(n)), where A138529(n) = Sum_{k=1..n} a(k).

1, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14

Offset

1,4

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Example

Runs (after the initial 1) each placed in parentheses:
(Notice that n-th run in parentheses contains exactly (Sum_{k=1..n} a(k)) terms.)
1, (1), (1, 2), (1, 2, 3), (1, 2, 3, 4, 5), (1, 2, 3, 4, 5, 6), (1, 2, 3, 4, 5, 6, 7, 8), (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11), (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14), (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17), ...

Mathematica

Nest[Flatten@Join[{1}, Range[Accumulate@#]] &, {1}, 4] (* Ivan Neretin, Jan 30 2018 *)

Crossrefs

Cf. A138529.

Sequence in context: A175022 A243613 A194844 * A364604 A037125 A194055

Adjacent sequences: A138525 A138526 A138527 * A138529 A138530 A138531

Keyword

easy,nonn

Author

Leroy Quet, Mar 23 2008

Status

approved