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 A200653 a(n) = greatest k with -3
 1, -1, 5, 0, -1, -1, 3, -1, 17, 0, 17, 23, 15, 17, 29, 9, 5, 5, 0, 11, -1, 15, 17, 41, 9, 0, 53, 45, 11, 0, 57, 35, 29, 39, 59, 0, 45, 5, 59, 57, 65, 71, 57, 47, 71, 75, 83, 29, 0, 41, 77, 45, 0, 29, 87, 107, 83, 105, 41, 107, 69, 113, 125, 111, 47, 125 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS There are only 11 0 values for n<434, and no more 0 values for n>433. If n>433, a(n) is > A200652. LINKS Pierre CAMI, Table of n, a(n) for n = 1..10000 MAPLE A200653 := proc(n) for k from 2*n-1 to -2 by -1 do if isprime(n*(n+1)+k) and isprime(n*(n+1)+k+2) then return k; end if; end do: return 0 ; end proc: seq(A200653(n), n=1..80) ; # R. J. Mathar, Nov 22 2011 CROSSREFS Cf. A200652. Sequence in context: A199916 A363041 A180494 * A058064 A316568 A198927 Adjacent sequences: A200650 A200651 A200652 * A200654 A200655 A200656 KEYWORD sign AUTHOR Pierre CAMI, Nov 20 2011 STATUS approved

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Last modified November 28 04:05 EST 2023. Contains 367394 sequences. (Running on oeis4.)