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

2, 5, 37, 4037923

Offset

1,1

Comments

Indices that give primes: 1, 2, 4, 10. - Michel Marcus, Jan 06 2014

a(5) corresponds to index 1006 and has 2586 decimal digits. - Giovanni Resta, Jan 06 2014

a(6) corresponds to index 8180 and has 28457 decimal digits. - Charles R Greathouse IV, Jan 08 2014

Links

Table of n, a(n) for n=1..4.

Mathematica

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

Prog

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

Crossrefs

Cf. A036782.

Sequence in context: A084436 A210482 A053609 * A051501 A221681 A347070

Adjacent sequences: A036777 A036778 A036779 * A036781 A036782 A036783

Keyword

nonn

Author

G. L. Honaker, Jr.

Extensions

Definition corrected by Michel Marcus, Jan 06 2014

Status

approved