A025156 - OEIS

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A025156

A prime number of consecutive composites follow n.

7, 8, 13, 14, 19, 20, 23, 25, 26, 31, 33, 34, 37, 38, 43, 44, 47, 49, 50, 53, 55, 56, 61, 63, 64, 67, 68, 73, 75, 76, 79, 80, 83, 85, 86, 89, 91, 93, 94, 97, 98, 103, 104, 109, 110, 113, 115, 119, 121, 123, 124, 127, 128, 131, 133, 134, 141, 143, 145

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

C. K. Caldwell, Composite Numbers.

EXAMPLE

a(1)=7 because 3 consecutive composites {8, 9 and 10} follow 7 and 3 is prime.

MATHEMATICA

Transpose[Select[Table[{n, NextPrime[n]-n-1}, {n, 300}], PrimeQ[ Last[#]]&]][[1]] (* Harvey P. Dale, May 26 2011 *)

CROSSREFS

Cf. A000040.