A095969 If p(k) is the k-th prime, then the n-th set of 2 consecutive cousin prime pairs starts at p(a(n)).

4, 6, 12, 25, 27, 29, 48, 63, 88, 93, 134, 147, 149, 151, 153, 181, 211, 224, 235, 247, 249, 285, 301, 389, 433, 483, 612, 642, 694, 742, 877, 975, 994, 1037, 1039, 1080, 1094, 1153, 1276, 1278, 1301, 1380, 1395, 1439, 1474, 1563, 1580, 1617, 1638, 1688

Offset

1,1

Links

Table of n, a(n) for n=1..50.

Example

a(2)=6: p(6)=13 and p(7)=17, the first cousin prime pair, p(8)=19 and p(9)=23, the second cousin prime pair.

Mathematica

n=0 Do[If[Prime[k + 1] - Prime[k]==4&&Prime[k + 3] - Prime[k + 2]==4, n = n + 1; Print[n, " ", k]], {k, 1, 1700}] (* Vincenzo Librandi, Jul 03 2015 *)

Prog

(Magma) [n: n in [1..2000] | NthPrime(n+1)-NthPrime(n) eq 4 and  NthPrime(n+3)-NthPrime(n+2) eq 4]; // Vincenzo Librandi, Jul 03 2015

Crossrefs

Sequence in context: A352634 A070232 A037100 * A090608 A197467 A256350

Adjacent sequences: A095966 A095967 A095968 * A095970 A095971 A095972

Keyword

nonn

Author

Ray G. Opao, Jul 15 2004

Status

approved