

A029544


Near Cullen numbers: k such that (k+1)*2^k + 1 is prime.


4



0, 1, 2, 5, 6, 13, 26, 65, 66, 86, 114, 133, 186, 294, 445, 866, 1325, 1478, 1823, 2765, 7553, 7943, 10178, 20960, 20964, 21337, 26562, 85374, 96749, 247038
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OFFSET

1,3


COMMENTS

Primes of the form n+1 are 2, 3, 7, 67, ...  _JuriStephan Gerasimov_, Oct 02 2011
Primes in the sequence are 2, 5, 13, 1823, 96749, ..  R. J. Mathar, Oct 15 2011
We can write (k+1)*2^k + 1 = {(k+1)/2}*4^{(k+1)/2} + 1, and when k is odd, this takes the form of a generalized Cullen prime (base 4). These are listed in A007646. In other words {2*A007646  1} gives all the odd members of this sequence.  Jeppe Stig Nielsen, Oct 16 2019


LINKS

Table of n, a(n) for n=1..30.
Steven Harvey, NearCullen and NearWoodall Primes


PROG

(PARI) isok(n) = isprime((n+1)*2^n+1); \\ Michel Marcus, Nov 09 2013


CROSSREFS

Cf. A002064, A007646, A230769.
Sequence in context: A154365 A247959 A243799 * A058668 A271640 A180744
Adjacent sequences: A029541 A029542 A029543 * A029545 A029546 A029547


KEYWORD

nonn,more


AUTHOR

Henri Lifchitz


EXTENSIONS

Corrected and extended by Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008


STATUS

approved



