A108893 - OEIS

A108893

Difference of primes pairs alternating between form 4k+3 and 4k+1.

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

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OFFSET

1,1

COMMENTS

a(n)>=4 because prime p and prime p + 2 (twin primes) are never at the same time of the form 4k+3 or 4k+1.

LINKS

Table of n, a(n) for n=1..94.

FORMULA

a(n) = A108811(2n) - A108811(2n-1).

EXAMPLE

a(1)=4 because the difference primes pairs of form 4k+3 11 and 7 = 4;

a(2)=4 because the difference primes pairs of form 4k+1 17 and 13 = 4.