OFFSET
1,1
LINKS
Giovanni Resta, Charles R Greathouse IV and Zak Seidov, Table of n, a(n) for n = 1..33
EXAMPLE
a(6)=463 because the first set of 7 consecutive primes is {463,467,479,487,491,499,503} with 6 gaps {4,12,8,4,8,4} all multiples of 4 while the next prime after 503 is 509 and 509-503=6 is not a multiple of 4.
PROG
(PARI) back(p, n)=while(n, p=precprime(p-1); n--); p
v=vector(20); g=0; p=2; forprime(q=3, 1e6, if((q-p)%4, if(g&&g<=#v&&v[g]==0, v[g]=back(p, g)); g=0, g++); p=q); v \\ Charles R Greathouse IV, Jul 14 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jun 24 2015
EXTENSIONS
a(13)-a(14) corrected by Charles R Greathouse IV, Jul 14 2015
a(24)-a(25) by Zak Seidov, Jul 15 2015
STATUS
approved