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A058272
An approximation to sigma_{5/2}(n): floor( sum_{d|n} d^(5/2) ).
3
1, 6, 16, 38, 56, 110, 130, 219, 259, 378, 402, 641, 610, 869, 943, 1243, 1192, 1728, 1574, 2199, 2167, 2678, 2537, 3644, 3181, 4062, 4047, 5050, 4529, 6283, 5351, 7036, 6673, 7938, 7433, 10034, 8328, 10481, 10124, 12499, 10764, 14426
OFFSET
1,2
LINKS
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_] := Floor[DivisorSigma[5/2, n]]; Array[a, 50] (* Amiram Eldar, Jan 14 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 08 2000
STATUS
approved