This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A301943 #34 Apr 04 2018 10:05:29
%S A301943 1,4,42,279,2236,18155,152020,1317648,11634451,104116591,942191087
%N A301943 Number of primes of the form b^2+1 for b <= 10^n that end in 1.
%F A301943 a(n) + A301944(n) + 2 = A206709(n).
%e A301943 101, 401, 1601 and 8101 are primes; so a(2) = 4.
%t A301943 c = k = 0; lst = {}; Do[ While[k <= 10^n, If[ PrimeQ[k^2 + 1], c++]; k+=10]; AppendTo[lst, c]; Print[c], {n, 9}] (* _Robert G. Wilson v_, Mar 30 2018 *)
%o A301943 (Python)
%o A301943 from sympy import isprime
%o A301943 def A301943(n):
%o A301943 return sum(1 for i in range(1,10**(n-1)+1) if isprime(100*i**2+1)) # _Chai Wah Wu_, Mar 30 2018
%Y A301943 Cf. A002496, A206709, A301944.
%K A301943 nonn,more,base
%O A301943 1,2
%A A301943 _Seiichi Manyama_, Mar 29 2018
%E A301943 a(10) from _Robert G. Wilson v_, Mar 31 2018
%E A301943 a(11) from _Robert G. Wilson v_, Apr 04 2018