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 A101411 #5 Dec 27 2024 13:43:06
%S A101411 2,5,12,29,169,408,470832,6625109,44560482149,345869461223138161,
%T A101411 13558774610046711780701,
%U A101411 87275373599917999482560755526644279276078854297832438763690789
%N A101411 Denominator when the numerator of the continued fraction rational approximation of sqrt(2) is prime. Also the denominators of A086395(n).
%t A101411 Select[Convergents[Sqrt[2],200],PrimeQ[Numerator[#]]&]//Denominator (* _Harvey P. Dale_, Dec 27 2024 *)
%o A101411 (PARI) cfracnum(m,f) = { local(x,r,cfr,i,m1); default(realprecision,3000); numer2=0; denom2=0; cfr = vector(m+100); x=f; for(n=0,m, i=floor(x); x=1/(x-i); cfr[n+1] = i; ); for(m1=0,m, r=cfr[m1+1]; forstep(n=m1,1,-1, r = 1/r; r+=cfr[n]; ); numer=numerator(r); denom=denominator(r); if(ispseudoprime(numer),print1(denom",")); ); default(realprecision,28);
%Y A101411 Cf. A086395.
%K A101411 frac,nonn
%O A101411 1,1
%A A101411 _Cino Hilliard_, Jan 15 2005