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Primes associated with A127435.
4

%I #7 Jun 08 2016 11:13:06

%S 2,5,17,37,101,257,1297,1601,4357,15877,16901,22501,24337,32401,44101,

%T 57601,62501,65537,72901,78401,93637,156817,160001,176401,184901,

%U 217157,240101,309137,324901,331777,417317,476101,490001,562501,577601,682277

%N Primes associated with A127435.

%C A sequence with P=a(k) distinct numbers contains a subsequence of p=A127435(k) monotonically increasing or decreasing terms, according to a corollary of the Erdos-Szekeres theorem.

%F a(n) = (A127435(n)-1)^2 + 1.

%t Select[(Prime@Range[300] - 1)^2 + 1, PrimeQ] (* _Ray Chandler_, Jan 23 2007 *)

%o (PARI) listp(nn) = {forprime(p=2, nn, if (isprime(q=(p-1)^2 + 1), print1(q, ", ")););} \\ _Michel Marcus_, Jun 08 2016

%Y Cf. A127435. Subsequence of A045349.

%K nonn

%O 1,1

%A _Lekraj Beedassy_, Jan 14 2007

%E Corrected and extended by _Ray Chandler_, Jan 23 2007