A082075 First differences of primes of the form 4*k+3 (A002145).

4, 4, 8, 4, 8, 12, 4, 12, 8, 4, 8, 4, 20, 4, 20, 4, 8, 12, 12, 4, 12, 12, 8, 12, 12, 4, 12, 12, 12, 8, 12, 24, 4, 20, 16, 12, 8, 12, 4, 36, 12, 8, 4, 20, 4, 12, 8, 4, 8, 4, 20, 24, 16, 8, 16, 12, 8, 12, 12, 12, 4, 12, 24, 8, 28, 8, 12, 4, 8, 36, 24, 12, 4, 12, 20, 4, 20, 4, 20, 4, 8, 28, 20, 4

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A002145(n+1) - A002145(n).

Example

The first and second primes of the form 4*k+3 are 3 and 7, so a(1) = 7-3 = 4.

Mathematica

k=0; m=4; r=3; Do[s=Mod[Prime[n], m]; If[Equal[s, r], rp=ep; k=k+1; ep=Prime[n]; Print[ep-rp]; ], {n, 1, 1000}]

Crossrefs

Cf. A002144, A002145, A082073, A082074, A082075, A082076.

Sequence in context: A273428 A273765 A273854 * A243641 A276620 A276681

Adjacent sequences: A082072 A082073 A082074 * A082076 A082077 A082078

Keyword

nonn

Author

Labos Elemer, Apr 07 2003

Status

approved