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A262783 Terms of A173143 (partial sums of squarefree numbers) that are square. 0
1, 144, 6084, 33856, 37636, 6310144, 10150596, 14668900, 20007729, 3292234884, 39600602001, 92437853419755481, 2849708967414258609 (list; graph; refs; listen; history; text; internal format)
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 14 first 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: A086985 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

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Last modified September 18 07:50 EDT 2019. Contains 327168 sequences. (Running on oeis4.)