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A036780 Primes of the form n + Sum_{i=1..n} i!. 0

%I

%S 2,5,37,4037923

%N Primes of the form n + Sum_{i=1..n} i!.

%C Indices that give primes: 1, 2, 4, 10. - _Michel Marcus_, Jan 06 2014

%C a(5) corresponds to index 1006 and has 2586 decimal digits. - _Giovanni Resta_, Jan 06 2014

%C a(6) corresponds to index 8180 and has 28457 decimal digits. - _Charles R Greathouse IV_, Jan 08 2014

%t With[{nn=40},Select[Total/@Thread[{Range[nn],Accumulate[Range[ nn]!]}], PrimeQ]] (* _Harvey P. Dale_, Feb 18 2018 *)

%o (PARI) lista(nn) = { for (n=1, nn, if (isprime(p = sum(i=1, n, i!) + n), print1(p, ", ")););} \\ _Michel Marcus_, Jan 06 2014

%Y Cf. A036782.

%K nonn

%O 1,1

%A _G. L. Honaker, Jr._

%E Definition corrected by _Michel Marcus_, Jan 06 2014

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Last modified March 8 10:20 EST 2021. Contains 341948 sequences. (Running on oeis4.)