A156024 a(n) = n*(n+1)/2 - A156022(n).
0, 1, 2, 4, 6, 9, 12, 15, 19, 23, 27, 32, 37, 42, 48, 54, 60, 66, 73, 80, 87, 94, 101, 109, 117, 125, 133, 142, 151, 160, 169, 178, 187, 197, 207, 217, 227, 238, 249, 260, 271, 282, 293, 304, 316, 328, 340, 352, 364, 377, 390, 402, 415, 428, 441, 454, 468, 482
Offset: 1
Links
- Martin Fuller, Table of n, a(n) for n = 1..80
- 2008/9 British Mathematical Olympiad Round 2, Problem 4, Jan 29 2009.
Crossrefs
Formula
c_1 + o(1) <= a(n)/n^1.5 <= c_2 + o(1) for some positive constants c_1 and c_2; it seems likely a(n)/n^1.5 tends to some positive constant limit.
Extensions
a(32) onwards from Martin Fuller, Jul 24 2025
Comments