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.
import Data.Set (singleton, notMember, insert)
a100208 n = a100208_list !! (n-1)
a100208_list = 1 : (f 1 [1..] $ singleton 1) where
f x (w:ws) s
| w `notMember` s &&
a010051 (x*x + w*w) == 1 = w : (f w [1..] $ insert w s)
| otherwise = f x ws s where
-- Reinhard Zumkeller, Apr 28 2011
nn = 100; unused = Range[2, nn]; t = {1}; While[k = 0; While[k++; k <= Length[unused] && ! PrimeQ[t[[-1]]^2 + unused[[k]]^2]]; k <= Length[unused], AppendTo[t, unused[[k]]]; unused = Delete[unused, k]]; t (* T. D. Noe, Apr 27 2011 *)
v=[1];n=1;while(n<100,if(isprime(v[#v]^2+n^2)&&!vecsearch(vecsort(v),n),v=concat(v,n);n=0);n++);v \\ Derek Orr, Jun 01 2015
from sympy import isprime A100208 = [1] for n in range(1,100): a, b = 1, 1 + A100208[-1]**2 while not isprime(b) or a in A100208: b += 2*a+1 a += 1 A100208.append(a) # Chai Wah Wu, Sep 01 2014
a[0]=1; a[1]=1; a[n_]:=a[n]= Block[{t = a[n-2] + 1}, While[! PrimeQ[t^2 + a[n-1]^2], t++]; t]; Array[a, 80, 0] (* Giovanni Resta, May 08 2016 *)
lista(nn) = {print1(x = 1, ", "); print1(y = 1, ", "); for (n=2, nn, z = x+1; while (! isprime(y^2+z^2), z++); print1(z, ", "); x = y; y = z;);} \\ Michel Marcus, May 08 2016
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