A046950 Square elements of A046949.

1, 25, 49, 169, 625, 1369, 3025, 7921, 18769, 37249, 208849, 3485689, 4950625, 7756225, 225150025, 48195616225, 264353307409, 453673643809, 1278932548201, 5225490897028249, 6290436331177441, 16712972707067569

Offset

0,2

Links

Table of n, a(n) for n=0..21.

Mathematica

Join[{1}, Table[ 24*Sum[ d*Mod[d, 2], {d, Divisors[n]}], {n, 1, 10^6}]] // Accumulate // Select[#, IntegerQ[Sqrt[#]] &] & (* Jean-François Alcover, Jul 02 2013 *)

Prog

(PARI) B=1; print1(B, ", "); for (n=1, 200000, t1=divisors(2*n); t2=0; for (i=1, length(t1), if( t1[ i ]%4 <> 0, t2=t2+t1[ i ])); B=B+8*t2; if (issquare(B), print1(B, ", ")))

Crossrefs

Sequence in context: A137659 A020325 A108604 * A146641 A171590 A322434

Adjacent sequences: A046947 A046948 A046949 * A046951 A046952 A046953

Keyword

nonn,nice,more

Author

N. J. A. Sloane

Extensions

a(17)-a(18) from Jason Earls, Jul 21 2001

a(19)-a(21) from Sean A. Irvine, May 07 2021

Status

approved