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A182156 Numbers k such that 2^k-61 is prime. 0
6, 7, 11, 15, 17, 21, 23, 25, 31, 35, 57, 67, 85, 165, 213, 217, 331, 351, 695, 721, 815, 825, 1007, 1403, 1725, 1833 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For these k, N=2^(k-1)*(2^k-61) is of abundance A033880(N)=60.

The five smallest numbers of abundance 60 are 96, 126, 4288, 2034688, 535871488. Four out of these five are of the form 2^(k-1)*(2^k-61).

LINKS

Table of n, a(n) for n=1..26.

PROG

(PARI) for(k=1, 999, ispseudoprime(2^k-61)&print1(k", "))

CROSSREFS

Sequence in context: A270431 A315832 A224856 * A166496 A267413 A297254

Adjacent sequences:  A182153 A182154 A182155 * A182157 A182158 A182159

KEYWORD

nonn,more

AUTHOR

M. F. Hasler, Apr 14 2012

STATUS

approved

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Last modified November 14 04:47 EST 2019. Contains 329108 sequences. (Running on oeis4.)