A126088 - OEIS

A126088

Least k such that k*(p(n+1)#-p(n)#)-1 and k*(p(n+1)#-p(n)#)+1 are twin primes.

1, 3, 1, 3, 2, 4, 13, 5, 9, 10, 6, 8, 61, 121, 3, 13, 17, 79, 45, 27, 120, 145, 113, 11, 41, 198, 102, 139, 202, 103, 23, 48, 177, 43, 486, 169, 501, 251, 106, 132, 40, 155, 1890, 116, 584, 107, 629, 241, 1331, 2078, 562, 57, 52, 71, 567, 73, 262, 332, 483, 419, 423

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OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..200

EXAMPLE

3*(2*3*5-2*3)-1=71 3*(2*3*5-2*3)+1=73; 71 and 73 twin primes so k(2)=3

MATHEMATICA

ktp[n_]:=Module[{k=1}, While[!PrimeQ[k*n-1]||!PrimeQ[k*n+1], k++]; k]; With[ {prmrls=#[[2]]-#[[1]]&/@Partition[FoldList[Times, Prime[Range[ 70]]], 2, 1]}, ktp/@prmrls] (* Harvey P. Dale, Mar 31 2017 *)

CROSSREFS

Sequence in context: A279633 A126208 A287863 * A363833 A294248 A085671

Adjacent sequences: A126085 A126086 A126087 * A126089 A126090 A126091

KEYWORD

nonn

AUTHOR

Pierre CAMI, Mar 03 2007

STATUS

approved