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 A335007 #7 May 19 2020 19:16:30
%S A335007 1,2,9,4,3,5,3,3,1,5,9,9,2,1,3,1,3,3,4,0,1,2,7,5,2,9,0,0,2,0,4,2,6,4,
%T A335007 8,6,6,8,9,1,2,8,3,2,3,3,4,9,3,7,0,9,1,5,6,7,2,7,9,2,9,1,9,0,6,4,5,5,
%U A335007 7,0,0,0,8,2,8,8,8,1,0,5,5,5,4,4,9,6,2
%N A335007 Decimal expansion of 2*(gamma - zeta'(2)/zeta(2)) - 1, where gamma is the Euler-Mascheroni constant.
%H A335007 Eckford Cohen, <a href="http://www.jstor.org/stable/2309455">The number of unitary divisors of an integer</a>, The American Mathematical Monthly, Vol. 67, No. 9 (1960), pp. 879-880.
%F A335007 Equals lim_{k->oo} ((zeta(2)/k)*A064608(k) - log(k)) where A064608 is the partial sums of the number of unitary divisors (A034444).
%F A335007 Equals 2*A001620 + 2*A073002/A013661 - 1 = 2*A335006 - 1.
%e A335007 1.2943533159921313340127529002042648668912832334937...
%t A335007 RealDigits[2*EulerGamma - 2*Zeta'[2]/Zeta[2] - 1, 10, 100][[1]]
%o A335007 (PARI) 2*Euler - 2*zeta'(2)/zeta(2) - 1 \\ _Michel Marcus_, May 19 2020
%Y A335007 Cf. A001620 (gamma), A013661 (zeta(2)), A034444, A064608, A073002 (-zeta'(2)), A147533, A335006.
%K A335007 nonn,cons
%O A335007 1,2
%A A335007 _Amiram Eldar_, May 19 2020