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 A140528 #18 Oct 18 2024 08:37:51
%S A140528 2,3,5,7,4,8,10,4,7,17,8,10,8,13,19,7,13,13,14,13,32,23,8,29,11,16,28,
%T A140528 23,10,19,19,38,32,37,38,29,23,41,37,28,31,41,25,38,41,28,26,41
%N A140528 Sum of digits of Mersenne prime exponents.
%F A140528 a(n) = A007953(A000043(n)). - _Michel Marcus_, Jul 15 2021
%e A140528 Since A000043(15) = 1279, a(15) = 1+2+7+9 = 19. - _Timothy L. Tiffin_, Jul 14 2021
%t A140528 Table[Plus @@ IntegerDigits[e], {e, MersennePrimeExponent[Range[47]]}] (* _Amiram Eldar_, Jul 16 2021 *)
%Y A140528 Cf. A000043, A007953.
%K A140528 nonn,base,more
%O A140528 1,1
%A A140528 _Edmund Algeo_, Jul 03 2008
%E A140528 a(39)-a(40) corrected by and a(41)-a(47) from _Timothy L. Tiffin_, Jul 14 2021
%E A140528 a(48) from _Amiram Eldar_, Oct 18 2024