A182375 Positive integers n such that n*2^n - 3 is prime.

2, 4, 5, 14, 16, 17, 34, 38, 133, 175, 218, 284, 1036, 1441, 1550, 2893, 2933, 3770

Offset

1,1

Comments

Similar to the Woodall primes, A050918.

The next term in this sequence is unknown; if it is infinite, the next term is greater than 8000.

Links

Table of n, a(n) for n=1..18.

Example

5 = 2*2^2 - 3;  61 = 4*2^4 - 3;  157 = 5*2^5 - 3

Maple

#choose N large, then S is the desired set
f:=n->n*2^n - 3:
S:={}:
for n from 0 to N do if(isprime(f(n))) then S:=S union {n}: fi: od

Crossrefs

Cf. A050918. Values for primes are A182352.

Sequence in context: A368378 A367298 A039574 * A295402 A121410 A002959

Adjacent sequences: A182372 A182373 A182374 * A182376 A182377 A182378

Keyword

nonn

Author

Patrick Devlin, Apr 26 2012

Status

approved