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 A110494 #19 Oct 30 2023 07:51:22
%S A110494 3,5,13,25,61,85,145,181,265,421,481,685,841,925,1105,1405,1741,1861,
%T A110494 2245,2521,2665,3121,3445,3961,4705,5101,5305,5725,5941,6385,8065,
%U A110494 8581,9385,9661,11101,11401,12325,13285,13945,14965,16021,16381,18241,18625,19405
%N A110494 Least k such that prime(n)^2 divides binomial(2k,k).
%C A110494 For prime p > sqrt(2n), p^2 does not divide binomial(2n,n).
%H A110494 Charles R Greathouse IV, <a href="/A110494/b110494.txt">Table of n, a(n) for n = 1..10000</a> (first 60 terms from T. D. Noe)
%F A110494 a(n) = (prime(n)^2+1)/2 for n > 1.
%F A110494 a(n) = A066885(n), n > 1. - _R. J. Mathar_, Aug 18 2008
%t A110494 t=Table[f=FactorInteger[Binomial[2n, n]]; s=Select[f, #[[2]]>1&]; If[s=={}, 0, s[[ -1, 1]]], {n, 100}]; Table[p=Prime[i]; First[Flatten[Position[t, p]]], {i, PrimePi[Max[t]]}]
%t A110494 lk[n_]:=Module[{k=1,c=Prime[n]^2},While[!Divisible[Binomial[2k,k],c], k=k+2]; k]; Array[lk,40] (* _Harvey P. Dale_, Oct 10 2012 *)
%o A110494 (PARI) fv(n,p)=my(s); while(n\=p, s+=n); s
%o A110494 a(n)=my(p=prime(n),k=p^2\2+1); while(fv(2*k,p)-2*fv(k,p)<2,k++); k \\ _Charles R Greathouse IV_, Mar 27 2014
%o A110494 (PARI) a(n)=prime(n)^2\2+1 \\ _Charles R Greathouse IV_, Mar 27 2014
%Y A110494 Cf. A110493 (largest prime p such that p^2 divides binomial(2n, n)).
%K A110494 nonn,easy
%O A110494 1,1
%A A110494 _T. D. Noe_, Jul 22 2005