A297841 a(n) = Sum_{d|n} max(d, n/d)^2.

1, 8, 18, 36, 50, 90, 98, 160, 171, 250, 242, 392, 338, 490, 500, 656, 578, 882, 722, 1050, 980, 1210, 1058, 1640, 1275, 1690, 1620, 2058, 1682, 2522, 1922, 2688, 2420, 2890, 2548, 3726, 2738, 3610, 3380, 4328, 3362, 4900, 3698, 5082, 4662, 5290, 4418, 6688

Offset

1,2

Links

Seiichi Manyama, Table of n, a(n) for n = 1..10000

Formula

a(n) = 2*A001157(n) - A297792(n).

Maple

f:= n -> add(max(d, n/d)^2, d = numtheory:-divisors(n)):
map(f, [$1..100]); # Robert Israel, Jan 10 2018

Mathematica

f[n_] := Block[{d = Divisors@ n}, Plus @@ (Max[#, n/#]^2 & /@ d)]; Array[f, 50] (* Robert G. Wilson v, Jan 07 2018 *)

Prog

(PARI) {a(n) = sumdiv(n, d, max(d, n/d)^2)}

Crossrefs

Sum_{d|n} max(d, n/d)^k: A117003 (k=1), this sequence (k=2), A297842 (k=3), A297843 (k=4), A297844 (k=5).

Cf. A001157, A297792.

Sequence in context: A120091 A211526 A211528 * A098944 A129958 A082227

Adjacent sequences: A297838 A297839 A297840 * A297842 A297843 A297844

Keyword

nonn

Author

Seiichi Manyama, Jan 07 2018

Status

approved