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A363392
Sum of divisors of 4*n-2 of form 4*k+3.
1
0, 3, 0, 7, 3, 11, 0, 18, 0, 19, 10, 23, 0, 30, 0, 31, 14, 42, 0, 42, 0, 43, 18, 47, 7, 54, 0, 66, 22, 59, 0, 73, 0, 67, 26, 71, 0, 93, 18, 79, 30, 83, 0, 90, 0, 98, 34, 114, 0, 113, 0, 103, 60, 107, 0, 114, 0, 138, 42, 126, 11, 126, 0, 127, 46, 131, 26, 180, 0, 139, 50, 154, 0, 157, 0, 151, 54, 186, 0, 162, 30
OFFSET
1,2
FORMULA
a(n) = A050452(4*n-2).
G.f.: Sum_{k>0} (4*k-1) * x^(2*k) / (1 - x^(4*k-1)).
MATHEMATICA
a[n_] := DivisorSum[4*n - 2, # &, Mod[#, 4] == 3 &]; Array[a, 100] (* _Amiram Eldar_, Jul 08 2023 *)
PROG
(PARI) a(n) = sumdiv(4*n-2, d, (d%4==3)*d);
CROSSREFS
KEYWORD
nonn
AUTHOR
_Seiichi Manyama_, Jul 08 2023
STATUS
approved