A182353 Primes of the form n*2^n - 5.

3, 19, 59, 379, 4603, 1048571, 44040187, 7516192763, 6614661952700411, 13510798882111483, 477381560501272571, 16717361816799281147, 4869940435459321626619, 802726744224113772004900859

Offset: 1

Author

Patrick Devlin, Apr 25 2012

Keywords

• nonn

Comments

These are similar to the Woodall primes, A050918, and to sequence A182352, which are primes of the form n*2^n - 1 and of the form n*2^n - 3 respectively. However, this sequence seems to grow rather more slowly than those.

Examples

			3 = 2*2^2 - 5;  19 = 3*2^3 - 5;  59 = 4*2^4 - 5.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..26

Crossrefs

Cf. A050918, A182352.

Programs

Maple

#choose N large, then S is the desired set
f:=n->n*2^n - 5:
S:={}:
for n from 0 to N do if(isprime(f(n))) then S:=S union {f(n)}: fi: od

Mathematica

Select[Table[n*2^n-5,{n,2,100}],PrimeQ] (* Harvey P. Dale, Aug 06 2013 *)