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A121999
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Primes p such that p^2 divides Sierpinski number A014566[(p-1)/2].
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5
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OFFSET
| 1,1
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COMMENTS
| A014566[n] = n^n + 1. a(n) is a subset of A003628[n] Primes congruent to {5, 7} mod 8, because prime p divides A014566[(p-1)/2] iff p belong to A003628[n].
No other terms below 10^11. [From Max Alekseyev (maxale(AT)gmail.com), Sep 18 2010]
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LINKS
| Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics. Sierpinski Number of the First Kind.
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FORMULA
| Elements of A125854 congruent to 5 or 7 modulo 8, i.e., primes p such that p == 5 or 7 (mod 8) and 2^(p-1) == 1+p (mod p^2). [From Max Alekseyev (maxale(AT)gmail.com), Sep 18 2010]
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MATHEMATICA
| Do[p=Prime[n]; f=((p-1)/2)^((p-1)/2)+1; If[IntegerQ[f/p^2], Print[p]], {n, 1, 3373}]
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PROG
| (PARI) { forprime(p=3, 10^11, if(Mod((p-1)/2, p^2)^((p-1)/2)==-1, print(p); )) } [From Max Alekseyev (maxale(AT)gmail.com), Sep 18 2010]
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CROSSREFS
| Cf. A014566, A003628.
Sequence in context: A167470 A152865 A108272 * A069530 A087144 A114616
Adjacent sequences: A121996 A121997 A121998 * A122000 A122001 A122002
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KEYWORD
| bref,more,nonn
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AUTHOR
| Alexander Adamchuk (alex(AT)kolmogorov.com), Sep 11 2006
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