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 A134712 #13 Oct 21 2024 04:35:54
%S A134712 0,0,1,2,7,10,11,22,51,78,95,114,507,592,1263,2186,2263,3198,4233,
%T A134712 4402,9667,9918,11189,19912,21675,23182,44469,86214,110473,132018,
%U A134712 216059,756806,859399,1257752,1398233,2976184,3021339,6972554,13466877
%N A134712 Base-2 logarithm of (n-th even superperfect number divided by 2^n).
%H A134712 Amiram Eldar, <a href="/A134712/b134712.txt">Table of n, a(n) for n = 1..48</a>
%H A134712 Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>.
%F A134712 a(n) = log_2(A061652(n)/(2^n)) = A000043(n) - n - 1 = A090748(n) - n.
%e A134712 a(5) = 7 because the 5th even superperfect number is 4096, 2^5 = 32, 4096/32 = 128 and log_2(128) = 7 (because 2^7 = 128).
%t A134712 With[{max = 48}, MersennePrimeExponent[Range[max]] - Range[max] - 1] (* _Amiram Eldar_, Oct 21 2024 *)
%Y A134712 Cf. A000043, A000396, A000668, A019279, A061652, A090748, A133028.
%K A134712 nonn
%O A134712 1,4
%A A134712 _Omar E. Pol_, Nov 07 2007