A025213 a(n) = floor(3rd elementary symmetric function of Sum_{j=1..k} 1/j, k = 1,2,...,n).

2, 15, 49, 122, 255, 472, 804, 1284, 1950, 2842, 4005, 5488, 7341, 9619, 12380, 15683, 19594, 24177, 29503, 35642, 42669, 50662, 59699, 69863, 81238, 93910, 107969, 123505, 140612, 159386, 179924, 202326, 226695, 253132, 281746, 312643, 345934, 381729

Offset

3,1

Links

Robert Israel, Table of n, a(n) for n = 3..300

Maple

es3:= proc(L) convert(map(convert, combinat:-choose(L, 3), `*`), `+`) end proc:
f:= proc(n) local k; floor(es3(ListTools:-PartialSums([seq(1/k, k=1..n)]))) end proc:
map(f, [$3..50]); # Robert Israel, Dec 12 2022

Crossrefs

Sequence in context: A041719 A133777 A350383 * A362303 A290631 A116693

Adjacent sequences: A025210 A025211 A025212 * A025214 A025215 A025216

Keyword

nonn

Author

Clark Kimberling

Status

approved