OFFSET
1,1
FORMULA
a(n) = Min{x; gcd[prime(x)-1, ..., prime(x+n-1)] > 2}, where prime() = A000040().
EXAMPLE
For n = 2: a(2) = 6 = A067605(2).
For 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;
PROG
(PARI) a(n) = {my(k = 0, v = vector(n, i, prime(i)-1)); if(gcd(v) > 2, return(0)); forprime(p = v[n]+1, , k++; v = concat(vecextract(v, "^1"), p-1); if(gcd(v) > 2, return(k))); } \\ Amiram Eldar, Jun 22 2024
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Labos Elemer, Feb 26 2003
EXTENSIONS
a(1) corrected and a(17)-a(26) added by Amiram Eldar, Jun 22 2024
STATUS
approved