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
KEYWORD
easy,nonn
AUTHOR
Leroy Quet, Mar 23 2008
STATUS
approved