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A110979
Squares equal to the sum of the first k primes minus 1.
2
1, 4, 9, 16, 196, 839056, 7796654478001
OFFSET
1,2
COMMENTS
No more terms < 7472966967498, sum of first 10^6 primes minus 1. - Ray Chandler, Oct 07 2005
MATHEMATICA
Select[Accumulate[Prime[Range[1000]]]-1, IntegerQ[Sqrt[#]]&] (* Harvey P. Dale, Jun 09 2022 *)
PROG
(PARI) lista(nn) = my(s=-1); forprime(p=2, nn, s+=p; if(issquare(s), print1(s, ", "))) \\ Jinyuan Wang, Aug 10 2023
CROSSREFS
Intersection of A000290 and A237589.
Sequence in context: A089149 A082920 A204434 * A073173 A313352 A253601
KEYWORD
nonn,hard,more
AUTHOR
Giovanni Teofilatto, Sep 30 2005
EXTENSIONS
a(6) corrected by Ray Chandler, Oct 07 2005
a(7) from Jinyuan Wang, Aug 10 2023
STATUS
approved