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 A051276 #25 Mar 22 2024 18:17:41 %S A051276 2,1,2,1,3,4,2,3,3,2,2,4,1,3,2,4,4,3,4,4,1,2,4,1,4,1,1,3,1,4,1,4,2,1, %T A051276 1,3,3,2,2,4,4,2,4,3,1,2,4,3,3,3,3,1,3,1,1,3,3,4,1,3,3,3,4,2,2,2,1,4, %U A051276 1,1,4,4,2,1,2,3,4,4,4,2,2,1,3,1,3,2,4,2,1,4,3,4,3,1,2,1,3,3,3,1,1,3,1,2,2 %N A051276 Nonzero coefficients in one of the 5-adic expansions of sqrt(-1). %D A051276 Kurt Mahler, Introduction to p-adic numbers and their functions. Cambridge Tracts in Mathematics, 76. Cambridge University Press, Cambridge-New York, 1971. See pp. 35ff. %e A051276 2 + 1*5 + 2*5^2 + 1*5^3 + 3*5^4 + 4*5^5 + 2*5^6 + 3*5^7 + 3*5^9 + 2*5^10 + 2*5^11 + 4*5^13 + 1*5^14 + 3*5^15 + 2*5^16 + 4*5^17 + 4*5^19 + ... %p A051276 R:= select(t -> padic:-ratvaluep(t,1)=2,[padic:-rootp(x^2+1,5,200)]): %p A051276 subs(0=NULL,op([1,1,3],R)); # _Robert Israel_, Mar 04 2016 %o A051276 (PARI) sqrt(-1+O(5^100)) %Y A051276 Cf. A034935, A048898, A048899, A210850, A210851. %K A051276 nonn,easy,nice %O A051276 0,1 %A A051276 _N. J. A. Sloane_ %E A051276 More terms from Antonio G. Astudillo (afg_astudillo(AT)hotmail.com) and _Jason Earls_, Jun 15 2001 %E A051276 Name corrected by _Robert Israel_ at the suggestion of _Wolfdieter Lang_, Mar 04 2016