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 A121371 Least number k such that (k*M(n))^2 + k*M(n) - 1 and (k*M(n))^2 + k*M(n) + 1 are twin primes with M(i)=i-th Mersenne prime. 1
 1, 3, 5, 8, 99, 275, 278, 409, 96, 1538, 1253, 15858, 189168, 119552, 221444, 1047122, 3571449 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS EXAMPLE M(2)=2^3-1=7 7^2+7-1=55 composite (2*7)^2+2*7-1=209 composite (3*7)^2+3*7-1=461 prime, 461 and 463 are twin primes so k(2)=3 CROSSREFS Cf. A121370. Sequence in context: A174529 A174442 A109342 * A067094 A272235 A058642 Adjacent sequences:  A121368 A121369 A121370 * A121372 A121373 A121374 KEYWORD hard,more,nonn AUTHOR Pierre CAMI, Jul 24 2006 STATUS approved

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