A046728 Let p1, p2 be first pair of consecutive primes with difference 2n; let p3, p4 be 2nd such pair; sequence gives "wadi" value p3-p1.

2, 6, 8, 270, 42, 12, 180, 102, 546, 750, 822, 510, 660, 300, 534, 5208, 7140, 3302, 7800, 1476, 18840, 20706, 9570, 44960, 13986, 5862, 4672, 71118, 14538, 59370, 156348, 17688, 59184, 155736, 1782, 328694, 110370, 119616, 93402, 76116

Offset: 1

Author

Enoch Haga

Keywords

• nonn

Examples

			First consecutive prime pair having difference 60 is p1=43331, p2=43391; next is p3=102701, p4=102761; so a(30)=102701-43331=59370.
		

References

• Enoch Haga, Exploring Prime Numbers on Your PC, 2nd edition, 1998, ISBN 1-885794-16-9, Table 5, pp. 40-41.

Links

• Robert G. Wilson v, Table of n, a(n) for n = 1..201

Crossrefs

Cf. A038460, A038343. a(i)=b(i)-c(i) where b(i) is A046789 and c(i) is A000230.

Programs

Mathematica

Flatten[Table[Differences[First /@ Take[Select[Partition[Prime[Range[60000]], 2, 1], Differences[#] == {2 n} &], 2]], {n, 40}]] (* Jayanta Basu, Jun 27 2013 *)

PARI

a(n)=my(k,p=2,p1);forprime(q=3,,if(q-p==2*n,if(k++>1,return(p-p1),p1=p));p=q) \\ Charles R Greathouse IV, Jun 27 2013

Formula

a(n) = A046789(n) - A000230(n). - Robert G. Wilson v, Nov 26 2020

Extensions

More terms from Jud McCranie

a(31) inserted by Jayanta Basu, Jun 27 2013