OFFSET
1,1
COMMENTS
As N increases, the ratio sum(a(n)/n^2)/N for n = 1 to N tends to 4.
LINKS
Pierre CAMI, Table of n, a(n) for n = 1..272
EXAMPLE
10^1+3 = 13, 13 and 17 primes of gap 4, a(1)=3.
10^2+3 = 103, 103 and 107 primes of gap 4, a(2)=3.
PROG
(PARI) a(n) = {p = nextprime(10^n); q = nextprime(p+1); while (q-p != 4, r = nextprime(q+1); p = q; q = r); p - 10^n; } \\ Michel Marcus, Feb 24 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Pierre CAMI, Jul 11 2013
EXTENSIONS
Missing a(246) inserted into b-file by Andrew Howroyd, Feb 24 2018
STATUS
approved