1,7

T. D. Noe, Table of n, a(n) for n=1..10000

a(7)=2 because 14+3 and 14+5 are primes.

For[lst={}; n=1, n<=100, n++, cnt=0; k=1; While[Prime[k]<n, If[PrimeQ[2n+Prime[k]], cnt++ ]; k++ ]; AppendTo[lst, cnt]]; lst

Cf. A071137.

Sequence in context: A143488 A201159 A047070 * A029381 A343558 A297877

Adjacent sequences: A071124 A071125 A071126 * A071128 A071129 A071130

easy,nonn

T. D. Noe, May 28 2002

approved