1,1

Or, numbers n such that Sum_{d|n} d! is prime.

The prime 26951 from A002981 (n!+1 is prime) is a member since Sum_{d|n} d! = n!+1 if n is prime. - Jonathan Sondow (jsondow(AT)alumni.princeton.edu), Jan 30 2005

a(n) are the primes in A002981[n] = {0, 1, 2, 3, 11, 27, 37, 41, 73, 77, 116, 154, 320, 340, 399, 427, 872, 1477, 6380, 26951, ...} Numbers n such that n! + 1 is prime. Corresponding primes of the form p! + 1 are listed in A103319[n] = {3, 7, 39916801, 13763753091226345046315979581580902400000001, 33452526613163807108170062053440751665152000000001, ...}. - Alexander Adamchuk (alex(AT)kolmogorov.com), Sep 23 2006

Sum_{d|3} d! = 1! + 3! = 7 is prime, so 3 is a member.

Select[Prime[Range[5! ]], PrimeQ[ #!+1]&] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 17 2009]

Cf. A062363, A002981.

Cf. A002981, A088332, A038507, A103317, A103319, A002982.

Sequence in context: A006497 A038912 A019361 this_sequence A084121 A088747 A007756

Adjacent sequences: A093801 A093802 A093803 this_sequence A093805 A093806 A093807

more,nonn,new

Jason Earls (zevi_35711(AT)yahoo.com), May 19 2004

One more term from Alexander Adamchuk (alex(AT)kolmogorov.com), Sep 23 2006