A071701 Number of twin prime pairs <= n of form (4*k+1,4*k+3), k>0.

0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4

Offset

1,17

Comments

As for A071538 the convention is followed that a twin prime pair is <= n if its smaller member is <= n.

Links

Table of n, a(n) for n=1..96.

Example

a(30)=3, since (29,31) is included along with (5,7) and (17,19).

Crossrefs

a(n) = A071538(n) - A071702(n), cf. A071695, A071696.

Sequence in context: A179076 A095861 A111855 * A342696 A064459 A279758

Adjacent sequences: A071698 A071699 A071700 * A071702 A071703 A071704

Keyword

nonn

Author

Reinhard Zumkeller, Jun 04 2002

Status

approved