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A138581 Numbers n such that 2^(2*n-15)-15 is prime. 0
8, 9, 10, 11, 19, 55, 125 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..7.

EXAMPLE

2^(2*11-15)-15=113, 2^(2*19-15)-15=8388593, 2^(2*55-15)-15=39614081257132168796771975153, ...

MATHEMATICA

q=15; For[i=q, i<=q, a={}; Do[x=2^(2*n-i)-i; If[PrimeQ[x], AppendTo[a, n]], {n, 10^2}]; Print["2^(2*n-", i, ")-", i, " ", a]; i=i+2]

PROG

(PARI) is(n)=isprime(2^(2*n-15)-15) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A297134 A247455 A280290 * A323062 A097363 A152870

Adjacent sequences:  A138578 A138579 A138580 * A138582 A138583 A138584

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, May 13 2008

STATUS

approved

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Last modified October 19 03:20 EDT 2019. Contains 328211 sequences. (Running on oeis4.)