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 A061890 Squares that are the sum of initial primes. 9
 100, 25633969, 212372329, 292341604, 3672424151449, 219704732167875184222756 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The set of squares in A007504. - Zak Seidov, Oct 07 2015 LINKS Table of n, a(n) for n=1..6. G. L. Honaker Jr. and C. Caldwell, Prime Curios!: 9 Carlos Rivera, Problem 9: Sum of first k primes is perfect square, The Prime Puzzles & Problems Connection. FORMULA a(n) = A061888(n)^2. Intersection of A000290 and A007504. - Zak Seidov, Oct 08 2015 EXAMPLE 100 = 10^2 = 2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23, so 100 is in the sequence. MAPLE N:= 10^7: # to use primes up to N P:= select(isprime, [2, seq(2*i+1, i=1..floor(N/2))]): S:= ListTools:-PartialSums(P): select(issqr, S); # Robert Israel, Feb 16 2015 MATHEMATICA s[n_] := Sum[Prime[i], {i, 1, n}]; t := Table[s[n], {n, 20000}]; Select[t, IntegerQ[Sqrt[#]] &] (* Carlos Eduardo Olivieri, Feb 24 2015 *) PROG (PARI) lista() = {s = 0; forprime(p=2, , s += p; if (issquare(s), print1(s, ", ")); ); } \\ Michel Marcus, Mar 10 2015 CROSSREFS Cf. A007504, A033997, A033998, A061888. Cf. also A066527, A364691, A366269. Sequence in context: A343182 A013855 A204576 * A333024 A126686 A279028 Adjacent sequences: A061887 A061888 A061889 * A061891 A061892 A061893 KEYWORD nonn,more AUTHOR David W. Wilson, May 12 2001 EXTENSIONS Corrected by Vladeta Jovovic, May 21 2001 a(6) from Giovanni Resta, May 27 2003 Edited by Ray Chandler, Mar 20 2007 STATUS approved

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Last modified November 30 19:18 EST 2023. Contains 367462 sequences. (Running on oeis4.)