A317951
An S-automatic sequence for the system S = (a*b*, {a,b}, a
0, 1, 4, 2, 4, 4, 3, 4, 4, 4, 0, 4, 4, 4, 4, 1, 4, 4, 4, 4, 4, 2, 4, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4, 4, 4, 4, 0, 4, 4, 4, 4, 4, 4, 4, 4, 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 2, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 2
Offset: 0
Links
- Antti Karttunen, Table of n, a(n) for n = 0..22155
- Michel Rigo and Arnaud Maes, More on generalized automatic sequences, Journal of Automata, Languages and Combinatorics 7.3 (2002): 351-376. See Fig. 1.
Programs
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PARI
A317951(n) = if(ispolygonal(n,3), ((sqrtint(1+(n*8))-1)/2)%4, 4); \\ Antti Karttunen, Jan 17 2025
Formula
a(A000217(k)) = A010873(k) for any k; all other terms are equal to 4. - Andrey Zabolotskiy, Aug 20 2018
Extensions
Terms a(37) and beyond from Andrey Zabolotskiy, Aug 20 2018
Data section further extended to a(105) by Antti Karttunen, Jan 17 2025