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A030239 Smallest number such that a(n)*2^(2^n) +1 is prime. 0
1, 1, 1, 1, 1, 18, 12, 21, 102, 202, 826, 708, 502, 1522, 6223, 3493, 1063, 50655, 10051, 328426 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

LINKS

Table of n, a(n) for n=0..19.

FORMULA

a(n) = min{a : a > 0 and (a*2^2^n)! = -1 (mod a*2^2^n +1)}

CROSSREFS

Sequence in context: A194659 A194186 A033668 * A040308 A077810 A232505

Adjacent sequences:  A030236 A030237 A030238 * A030240 A030241 A030242

KEYWORD

nonn

AUTHOR

Alar Leibak (aleibak(AT)cyber.ee)

EXTENSIONS

a(11)-a(17) from Donovan Johnson, Mar 26 2010

a(18)-a(19) from Donovan Johnson, Jan 14 2012

STATUS

approved

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Last modified February 21 02:16 EST 2018. Contains 299388 sequences. (Running on oeis4.)