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 A034944 #21 Nov 11 2018 00:42:29
%S A034944 0,5,70,239,143044,1999509,6826318,822557039,85658552023,
%T A034944 1188526486815,11941488851037,291518510320809,2108769149874327,
%U A034944 13920898306972194,2675587335039691558,63228498770709057089
%N A034944 Successive approximations to 13-adic integer sqrt(-1).
%D A034944 K. Mahler, Introduction to p-Adic Numbers and Their Functions, Cambridge, 1973, p. 35.
%H A034944 Seiichi Manyama, <a href="/A034944/b034944.txt">Table of n, a(n) for n = 0..806</a>
%o A034944 (PARI) seq(n)={my(v=vector(n), i=1, k=0); while(i<#v, k++; my(t=truncate(sqrt(-1 + O(13^k)))); if(t > v[i], i++; v[i]=t)); v} \\ _Andrew Howroyd_, Nov 10 2018
%Y A034944 Cf. A034935, A034939, A218709, A286840.
%K A034944 nonn,easy
%O A034944 0,2
%A A034944 _N. J. A. Sloane_