A080373 a(n) is the smallest number such that GCD of n values of prime(j)-1 for successive j values is greater than 2, where prime(j)=j-th prime.

0, 6, 24, 77, 271, 271, 1395, 1395, 1395, 13717, 34369, 172146, 172146, 804584, 804584, 804584

Offset

1,2

Links

Table of n, a(n) for n=1..16.

Formula

a(n) = Min{x; gcd[prime(x)-1, ..., prime(x+n-1)]>2}, where prime()=A000040().

Example

n=2: a(2)=6=A067605(2);
n=3: a(3)=24 means: firstly occurs that for three consecutive p-1 terms GCD[prime(24)-1, prime(25)-1, prime(26)-1] = GCD[88, 96, 100] = 4 > 2;

Crossrefs

Cf. A058263, A067605.

Sequence in context: A225383 A257956 A341364 * A180437 A276179 A162583

Adjacent sequences: A080370 A080371 A080372 * A080374 A080375 A080376

Keyword

nonn,more

Author

Labos Elemer, Feb 26 2003

Status

approved