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 A231532 #12 Nov 12 2013 16:38:40
%S A231532 1,5,9,1,5,4,7,8,1,4,7,3,2,8,5,1,9,5,7,3,3,6,7,7,9,8,8,2,0,6,4,9,9,8,
%T A231532 2,7,6,2,4,6,0,5,9,2,6,7,4,7,8,6,8,0,0,9,2,5,4,5,3,5,3,2,5,7,0,7,6,3,
%U A231532 8,0,1,6,3,3,1,5,2,7,1,6,6,4,8,8,3,7,0,3,2,6,8,6,9,6,8,5,9,6,3,4,5,4,8,8,9
%N A231532 Decimal expansion of the real part of Sum_{n=0..inf}(1/c_n), c_0=1, c_n=c_(n-1)*(n+I).
%C A231532 Consider an extension of exp(x) to an intriguing function, expim(x,y), defined by the power series Sum_{n=0..inf}(x^n/c_n), where c_0 = 1, c_n = c_(n-1)*(n+y*I), so that exp(x) = expim(x,0). The current sequence regards the real part of expim(1,1). The decimal expansion of the imaginary part is in A231533 and that of the absolute value in A231534.
%H A231532 Stanislav Sykora, <a href="/A231532/b231532.txt">Table of n, a(n) for n = 1..10000</a>
%F A231532 real(Sum_{n=0..inf}(1/(A231530(n)+A231531(n)*I))).
%e A231532 1.59154781473285195733677988...
%o A231532 (PARI) Expim(x,y)={local (c,k,lastval,val);c = 1.0+0.0*I;lastval = c;k = 1; while (k,c*=x/(k + y*I);val = lastval + c;if (val==lastval, break); lastval = val;k += 1;);return (val);}
%o A231532 real(Expim(1,1))
%Y A231532 Cf. A231533 (imaginary part), A231534 (absolute value), and A231530, A231531 (respectively, the real and imaginary parts of the expansion coefficient's denominators).
%K A231532 nonn,cons
%O A231532 1,2
%A A231532 _Stanislav Sykora_, Nov 10 2013