A071326 Sum of squares > 1 dividing n.

0, 0, 0, 4, 0, 0, 0, 4, 9, 0, 0, 4, 0, 0, 0, 20, 0, 9, 0, 4, 0, 0, 0, 4, 25, 0, 9, 4, 0, 0, 0, 20, 0, 0, 0, 49, 0, 0, 0, 4, 0, 0, 0, 4, 9, 0, 0, 20, 49, 25, 0, 4, 0, 9, 0, 4, 0, 0, 0, 4, 0, 0, 9, 84, 0, 0, 0, 4, 0, 0, 0, 49, 0, 0, 25, 4, 0, 0, 0, 20, 90, 0, 0, 4, 0, 0, 0, 4, 0, 9, 0, 4, 0, 0, 0, 20, 0, 49, 9, 129

Offset

1,4

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

Formula

a(n) = A035316(n)-1.

Sum_{d|n, d>1} A010052(d). - Antti Karttunen, Nov 17 2017

Mathematica

Array[DivisorSum[#, # &, IntegerQ@ Sqrt@ # &] - 1 &, 100] (* Michael De Vlieger, Nov 17 2017 *)

Prog

(PARI) A071326(n) = sumdiv(n, d, (d>1)*issquare(d)*d); \\ Antti Karttunen, Nov 17 2017

Crossrefs

Cf. A000203, A010052, A071325, A071327.

One less than A035316.

Sequence in context: A272618 A265397 A071327 * A284103 A151674 A367631

Adjacent sequences: A071323 A071324 A071325 * A071327 A071328 A071329

Keyword

nonn

Author

Reinhard Zumkeller, May 18 2002

Extensions

More terms from Antti Karttunen, Nov 17 2017

Status

approved