A058274 An approximation to sigma_{5/2}(n): ceiling( sum_{d|n} d^(5/2) ).

1, 7, 17, 39, 57, 111, 131, 220, 260, 379, 403, 642, 611, 870, 944, 1244, 1193, 1729, 1575, 2200, 2168, 2679, 2538, 3645, 3182, 4063, 4048, 5051, 4530, 6284, 5352, 7037, 6674, 7939, 7434, 10035, 8329, 10482, 10125, 12500, 10765, 14427

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

Sum_{k=1..n} a(k) ~ (2/7)*zeta(7/2) * n^(7/2). - Amiram Eldar, Jan 14 2023

Maple

f := proc(n) local d, t1, t2; t2 := 0; t1 := divisors(n); for d in t1 do t2 := t2 + d^(5/2) end do; t2; end proc; # exact value of sigma_{5/2}(n)

Mathematica

a[n_] := Ceiling[DivisorSigma[5/2, n]]; Array[a, 50] (* Amiram Eldar, Jan 14 2023 *)

Crossrefs

Cf. A000203, A001157, A058272, A058273, A261804.

Sequence in context: A298369 A213789 A058273 * A322597 A360428 A193214

Adjacent sequences: A058271 A058272 A058273 * A058275 A058276 A058277

Keyword

nonn

Author

N. J. A. Sloane, Dec 08 2000

Status

approved