A050450 a(n) = Sum_{d|n, d=1 mod 4} d^2.

1, 1, 1, 1, 26, 1, 1, 1, 82, 26, 1, 1, 170, 1, 26, 1, 290, 82, 1, 26, 442, 1, 1, 1, 651, 170, 82, 1, 842, 26, 1, 1, 1090, 290, 26, 82, 1370, 1, 170, 26, 1682, 442, 1, 1, 2132, 1, 1, 1, 2402, 651, 290, 170, 2810, 82, 26, 1, 3250, 842, 1, 26, 3722, 1, 523, 1, 4420

Offset

1,5

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Mathematica

a[n_]:=Sum[d^2, {d, Select[Divisors[n], Mod[#, 4]==1 &]}]; Array[a, 60] (* Stefano Spezia, Feb 03 2026 *)

Prog

(Haskell)
a050450 = sum . map (^ 2) . filter ((== 1) . (`mod` 4)) . a027750_row
-- Reinhard Zumkeller, Jun 17 2013

Crossrefs

Cf. A027750, A050453.

Sequence in context: A040682 A040683 A040684 * A040680 A040679 A040678

Adjacent sequences: A050447 A050448 A050449 * A050451 A050452 A050453

Keyword

nonn

Author

N. J. A. Sloane, Dec 23 1999

Status

approved