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 A139789 #10 Jan 25 2019 18:57:18
%S A139789 0,0,1,1,2,2,3,3,4,4,4,4,5,5,6,6,6,6,6,7,7,7,8,8,8,9,9,10,10,11,11,12,
%T A139789 12,12,12,12,12,12,13,13,13,13,13,13,14,14,14,14,15,15,16,16,16,16,16,
%U A139789 16,16,16,16,17,17,17,17,18,18,19,19,19,19,19,20,20,20,20,20,21,21,21
%N A139789 Numbers of primes < n-th-prime such that prime(n) + 4 is prime.
%p A139789 A139789 := proc(n) local a,i; a := 0 ; for i from 1 to n-1 do if isprime(ithprime(i)+4) then a :=a +1 ; fi; od: a ; end: for n from 1 to 100 do printf("%d,",A139789(n)) ; od: # _R. J. Mathar_, Oct 05 2008
%t A139789 Join[{0},Accumulate[Table[If[PrimeQ[n+4],1,0],{n,Prime[Range[80]]}]]] (* _Harvey P. Dale_, Jan 25 2019 *)
%Y A139789 Cf. A082462.
%K A139789 nonn
%O A139789 1,5
%A A139789 _Giovanni Teofilatto_, May 21 2008
%E A139789 0 added in front, some 6's added and extended by _R. J. Mathar_, Oct 05 2008