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A108893 Difference of primes pairs alternating between form 4k+3 and 4k+1. 0
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 (list; graph; refs; listen; history; text; internal format)
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
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.
CROSSREFS
Cf. A108811, increasing consecutive prime pairs alternating between form 4k+3 and 4k+1.
Sequence in context: A059190 A085142 A064053 * A162281 A262690 A048760
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Jul 15 2005
EXTENSIONS
Extended by Ray Chandler, Jul 21 2005
STATUS
approved

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Last modified March 29 06:15 EDT 2024. Contains 371265 sequences. (Running on oeis4.)