

A119497


Primes of the form n! + n!! + 1.


0




OFFSET

1,1


REFERENCES

G. Balzarotti and P. P. Lava, Le sequenze di numeri interi, Hoepli, 2008, p. 159.


LINKS

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


EXAMPLE

For n=2, 2! + 2!! + 1 = 2 + 2 + 1 = 5, which is prime.
For n=6, 6! + 6!! + 1 = 720 + 48 + 1 = 769, which is prime.


MAPLE

SFACT:= proc(n) local i, j, k; for k from 1 by 1 to n do i:=k; j:=k2; while j >0 do i:=i*j; j:=j2; od: if isprime(k!+i+1) then print(k!+i+1); fi; od: end: SFACT(300);


PROG

(PARI) dfac(n)=prod(k=0, n\21, nkk)
for(n=1, 42, if(ispseudoprime(t=n!+dfac(n)+1), print1(t", "))); v \\ Charles R Greathouse IV, Feb 17 2011


CROSSREFS

Cf. A118769.
Sequence in context: A320939 A002427 A136134 * A298094 A012783 A062655
Adjacent sequences: A119494 A119495 A119496 * A119498 A119499 A119500


KEYWORD

nonn


AUTHOR

Paolo P. Lava and Giorgio Balzarotti, May 25 2006


EXTENSIONS

No more terms with fewer than a thousand digits.  Charles R Greathouse IV, Feb 17 2011


STATUS

approved



