A346759 a(n) = Sum_{d|n} floor(d^2/4).
0, 1, 2, 5, 6, 12, 12, 21, 22, 32, 30, 52, 42, 62, 64, 85, 72, 113, 90, 136, 124, 152, 132, 212, 162, 212, 204, 262, 210, 324, 240, 341, 304, 362, 324, 477, 342, 452, 424, 552, 420, 624, 462, 640, 590, 662, 552, 852, 612, 813, 724, 892, 702, 1024, 792, 1062, 904, 1052, 870, 1364
Offset: 1
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
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Maple
f:= proc(n) local d; add(floor(d^2/4),d=numtheory:-divisors(n)) end proc: map(f, [$1..100]); # Robert Israel, Dec 28 2023 -
Mathematica
Table[Sum[Floor[d^2/4], {d, Divisors[n]}], {n, 1, 60}] nmax = 60; CoefficientList[Series[Sum[x^(2 k)/((1 + x^k) (1 - x^k)^3), {k, 1, nmax}], {x, 0, nmax}], x] // Rest -
PARI
a(n) = sumdiv(n, d, d^2\4); \\ Michel Marcus, Aug 03 2021
Comments