%I
%S 2,13,68,560,4418,35953,304340,2636531,23265760,208241341,1884492541
%N Number of primes of the form b^2 + 1 for b <= 10^n that end in 7.
%F a(n) + A301943(n) + 2 = A206709(n).
%e 17, 37, 197, 257, 577, 677, 1297, 2917, 3137, 4357, 5477, 7057 and 8837 are primes; so a(2) = 13.
%Y Cf. A002496, A206709, A301943.
%K nonn,base,more
%O 1,1
%A _Seiichi Manyama_, Mar 29 2018
%E a(10)a(11) from _Jinyuan Wang_, Feb 24 2020
