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A113767 Values of the exponents in A084435. 1
0, 1, 2, 1, 5, 1, 1, 29, 3, 37, 31, 227, 835, 115, 7615, 6071, 218431 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

If A084435 ever hits a Sierpinski number, the sequence is finite.

a(18) > 10^5. - Harsh R. Aggarwal, Apr 11 2018

LINKS

Table of n, a(n) for n=1..17.

Eric Weisstein. "Sierpinski Number of the Second Kind."

PROG

(PARI) a=2; for(x=1, 16, for(k=0, 1000000, p=2^k*a+1; if(isprime(p), print(k); break)); a=p)

CROSSREFS

Cf. A084435, A113334, A121799.

Sequence in context: A323954 A143983 A282988 * A246964 A157334 A320667

Adjacent sequences:  A113764 A113765 A113766 * A113768 A113769 A113770

KEYWORD

nonn,hard,more

AUTHOR

Ken Takusagawa, Jan 19 2006

EXTENSIONS

a(16)-a(17) from Harsh R. Aggarwal, Apr 11 2018

STATUS

approved

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Last modified February 27 20:01 EST 2021. Contains 341658 sequences. (Running on oeis4.)