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A058271
An approximation to sigma_{3/2}(n): ceiling( sum_{d|n} d^(3/2) ).
4
1, 4, 7, 12, 13, 24, 20, 35, 34, 47, 38, 74, 48, 75, 76, 99, 72, 128, 84, 145, 121, 144, 112, 214, 138, 184, 174, 231, 158, 289, 174, 280, 233, 273, 238, 393, 227, 321, 297, 420, 264, 464, 283, 444, 405, 427, 324, 611, 363, 526, 441, 567, 387
OFFSET
1,2
LINKS
FORMULA
Sum_{k=1..n} a(k) ~ (2/5)*zeta(5/2) * n^(5/2). - 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^(3/2) end do; t2; end proc; # exact value of sigma_{3/2}(n)
MATHEMATICA
a[n_] := Ceiling[DivisorSigma[3/2, n]]; Array[a, 50] (* Amiram Eldar, Jan 14 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 08 2000
STATUS
approved