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 A209601 #16 Aug 09 2021 18:36:42 %S A209601 1,1,14,1,2,3,1,3,2,5,194,1,14,1,2,2,2,40,1,1,1,4,4,1,5,1,4,4,1,3,18, %T A209601 1,1,7,28,2,5,1,4,13,3,2,2,3,9,2,3,6,1,3,3,3,3,1,1,3,8,1,184,3,2,1,1, %U A209601 1,3,1,1,12,1,10,2,3,2,6,18,1,1,9 %N A209601 Continued fraction expansion of the sum of the reciprocals of the Mersenne primes (A000668). %H A209601 Charles R Greathouse IV, <a href="/A209601/b209601.txt">Table of n, a(n) for n = 1..10000</a> %t A209601 ContinuedFraction[Total[1/(2^MersennePrimeExponent[Range[30]]-1)],80] (* _Harvey P. Dale_, Aug 09 2021 *) %o A209601 (PARI) isM(p)=my(m=Mod(4,2^p-1));for(i=1,p-2,m=m^2-2);!m %o A209601 s=1/3;forprime(p=3,default(realprecision)*log(10)\log(2), if(isM(p), s+=1./(2^p-1)));v=contfrac(s);vector(#v-2,i,v[i+1]) \\ _Charles R Greathouse IV_, Mar 22 2012 %Y A209601 Cf. A000668, A173898, A209600. %K A209601 nonn,cofr %O A209601 1,3 %A A209601 _N. J. A. Sloane_, Mar 10 2012