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 A331549 #21 Mar 29 2025 10:50:47
%S A331549 6,8,10,13,11,4,13,4,2,6,0,7,5,8,14,12,9,14,2,12,8,7,9,8,5,6,7,14,10,
%T A331549 12,4,13,12,5,6,14,3,1,8,3,8,8,2,9,12,5,14,13,9,13,4,5,3,6,6,0,14,2,8,
%U A331549 14,13,13,2,0,12,1,9,1,0,5,4,2,0,5,8,8,14,2,2,7
%N A331549 15-adic integer x = ...8978C2E9CE8570624D4BDA86 satisfying x^2 = x.
%C A331549 The base-15 version of A018248. A, B, C, D, and E are the standard representations of the hexadecimal digits 10, 11, 12, 13, and 14, respectively.
%F A331549 x = 15-adic lim_{n->infinity} 3^(4*(5^n)).
%e A331549 x^2 = ...8978C2E9CE8570624D4BDA86 = x.
%o A331549 (PARI) \\ See A331548, with initial b=6 instead of b=3.
%o A331549 (PARI) A331549_vec(n)=Vecrev(digits(lift(chinese(Mod(0,3^n),Mod(1,5^n))),15)) \\ or simpler but slower: Vecrev(digits(lift(Mod(3^4,15^n)^5^(n-1)),15)) \\ _M. F. Hasler_, Jan 26 2020
%Y A331549 Cf. A018248.
%K A331549 nonn,base
%O A331549 0,1
%A A331549 _Patrick A. Thomas_, Jan 20 2020