A182374 Primes of the form n*3^n + 1.

19, 52489, 59296646043258913, 3140085798164163223281069127, 281013956365219695455558985684629594690518822413326510467

Offset: 1

Author

Patrick Devlin, Apr 26 2012

Keywords

• nonn

Comments

Similar to A060353, and to the Woodall primes A050918.

Examples

			19 = 2*3^2 + 1; 52489 = 8*3^8 + 1; a(3) = 32*3^32 + 1; a(4) = 54*3^54 + 1.
		

Crossrefs

Cf. A060353, A050918.

Programs

Maple

#choose N large, then S is the desired set
f:=n->n*3^n + 1:
S:={}:
for n from 0 to N do if(isprime(f(n))) then S:=S union {f(n)}: fi: od

Mathematica

Select[Table[n*3^n + 1, {n, 0, 580}], PrimeQ] (* Jayanta Basu, Jun 01 2013 *)