A111038 - OEIS

A111038

First i such that gcd(prime(i)+1, prime(i+1)+1, ..., prime(i+n)+1) > 2.

4, 15, 46, 90, 90, 90, 3875, 4165, 16591, 21355, 21355, 21355, 613491, 613491, 5541392, 6067263, 18351690, 25813464, 25813464, 39500857, 39500857, 947438659, 947438659, 947438659, 4645422093, 4645422093, 4645422093, 4645422093, 4645422093, 4645422093

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

For n=1, i=4 with primes (7, 11), so that gcd(8, 12) is 4 > 2.

For n=2, i=15 with primes (48, 54, 60), so that gcd(48, 54, 60) is 6 > 2.

PROG

(PARI) a(n) = {i = 0; v = 0; while(v <= 2, i++; v = prime(i)+1; for (k=1, n, v = gcd(v, prime(i+k)+1); if (v <= 2, break; ); ); ); return (i); } \\ Michel Marcus, May 19 2013

CROSSREFS

Sequence in context: A297088 A152116 A195688 * A188716 A100506 A173414

Adjacent sequences: A111035 A111036 A111037 * A111039 A111040 A111041

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Oct 05 2005

EXTENSIONS

a(8)-a(12) from Klaus Brockhaus, Oct 06 2005

a(13)-a(30) from Giovanni Resta, Jun 22 2015

STATUS

approved