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 A160600 Numbers n such that 3*(2n)^(2n)+1 is prime. 4
 1, 2, 3, 5, 143, 225 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This corresponds to the numbers such that 3m^m+1 is prime, but these must all be even, m=2n, and therefore it is more natural to record the sequence of n=m/2. Next term > 15000. - Matevz Markovic, Oct 09 2012 LINKS EXAMPLE a(1) = 1, because 2^2*3+1 = 13 is the smallest prime of this form. a(2) = 2, because 4^4*3+1 = 769 is the next smallest prime of this form. a(3) = 3, because 6^6*3+1 = 139969 is again a prime. PROG (PARI) for(i=1, 9999, ispseudoprime(i^i*3+1)&print1(i/2, ", ")) CROSSREFS Cf. A160360 (3n^n+2 is prime), A121270 = primes among Sierpinski numbers A014566(n)=n^n+1; A216148 = A216147(A110932): primes 2n^n+1; A088790, A065798. Sequence in context: A117702 A041343 A229349 * A325505 A319609 A140551 Adjacent sequences:  A160597 A160598 A160599 * A160601 A160602 A160603 KEYWORD hard,more,nonn AUTHOR M. F. Hasler, Jul 10 2009 STATUS approved

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Last modified July 30 19:33 EDT 2021. Contains 346359 sequences. (Running on oeis4.)