A262783 Terms of A173143 (partial sums of squarefree numbers) that are square.

1, 144, 6084, 33856, 37636, 6310144, 10150596, 14668900, 20007729, 3292234884, 39600602001, 92437853419755481, 2849708967414258609

Offset

1,2

Comments

Intersection of A000290 and A173143.

a(12) > 10^15. - Jon E. Schoenfield, Oct 11 2015

a(14) > 3*10^21. The first 13 terms are the sums of the first 1, 21, 141, 331, 354, 4555, 5785, 6949, 8110, 104070, 360930, 551460217, 3061889301 squarefree numbers. - Giovanni Resta, Aug 19 2018

Links

Table of n, a(n) for n=1..13.

Example

The sum of the first 14 squarefree integers is 1 + 2 + 3 + 5 + 6 + 7 + 10 + 11 + 13 + 14 + 15 + 17 + 19 + 21 = 144, a square.

Prog

(PARI) lista(nn) = {s = 0; i = 0; for (n=1, nn, if (issquarefree(n), i++; s += n; if (issquare(s), print1(s, ", ")); ); ); }

Crossrefs

Cf. A000290, A005117, A173143.

Sequence in context: A371251 A259318 A231744 * A182920 A299858 A308285

Adjacent sequences: A262780 A262781 A262782 * A262784 A262785 A262786

Keyword

nonn,more

Author

Michel Marcus, Oct 01 2015

Extensions

a(12)-a(13) from Giovanni Resta, Aug 19 2018

Status

approved