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A135368 a(n) = (nextprime(12*n) - previousprime(12*n))/2. 5
1, 3, 3, 3, 1, 1, 3, 4, 1, 7, 3, 5, 3, 3, 1, 1, 6, 6, 1, 1, 3, 3, 3, 5, 7, 1, 7, 3, 1, 4, 3, 3, 4, 4, 1, 1, 3, 4, 6, 4, 4, 3, 6, 9, 9, 5, 3, 3, 3, 1, 3, 6, 5, 3, 1, 6, 4, 5, 4, 4, 3, 4, 3, 4, 7, 5, 6, 5, 1, 7, 7, 7, 7, 10, 10, 4, 5, 4, 3, 7, 3, 4, 3, 6, 1, 1, 5, 5, 3, 9, 1, 3, 4, 3, 11, 1, 4, 5, 3, 4, 6, 3, 3, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n)=1 if 12n -/+ 1 are twin primes. Corresponding n's are in A124519: 1,5,6,9,15,16,19,20,26,29,35,36,50,...

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

MATHEMATICA

Table[ ( NextPrime[12*n, 1] - NextPrime[12*n, -1] )/2, {n, 1, 25}] (* G. C. Greubel, Oct 11 2016 *)

PROG

(PARI) a(n) = (nextprime(12*n) - precprime(12*n))/2; \\ Michel Marcus, Oct 12 2016

CROSSREFS

Cf. A124519, A135023.

Sequence in context: A064353 A190906 A080311 * A172358 A119560 A172364

Adjacent sequences:  A135365 A135366 A135367 * A135369 A135370 A135371

KEYWORD

nonn

AUTHOR

Zak Seidov, Feb 17 2008

STATUS

approved

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Last modified July 14 08:33 EDT 2020. Contains 335720 sequences. (Running on oeis4.)