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 A367608 #17 Jul 09 2025 05:03:25 %S A367608 4,7,1,-1,7,2,4,7,1,4,8,1,4,8,1,5,8,2,5,7,2,-1,7,2,4,7,1,4,7,1,4,7,1, %T A367608 4,7,1,4,7,1,4,7,1,4,7,1,4,8,1,4,8,1,5,8,2,5,8,2,5,8,2,5,8,2,5,8,2,5, %U A367608 8,2,5,8,2,5,7,2,-1,7,2,4,7,1,4,7,1,4,7,1,4,7,1,4,7,1,4,7,1,4,7,1,4 %N A367608 Comma-number associated with A367606(n), but written in base 10, or -1 if A367606(n) = -1. %C A367608 If n has a comma-successor m (say) in base 3, then a(n) is the comma-number linking n and m, and is equal to m-n; a(n) = -1 if n has no successor. See A367338 for definitions. %C A367608 This is a base-3 analog of A367339. %H A367608 Michael S. Branicky, <a href="/A367608/b367608.txt">Table of n, a(n) for n = 1..10000</a> %o A367608 (Python) %o A367608 from sympy.ntheory.factor_ import digits %o A367608 def a(n): %o A367608 b = n + 3*(n%3) %o A367608 return next((b+y-n for y in [1, 2] if digits(b+y, 3)[1] == y), -1) %o A367608 print([a(n) for n in range(1, 101)]) # _Michael S. Branicky_, Dec 11 2023 %Y A367608 Cf. A121085, A367339, A367355, A367356, A367606-A367609. %K A367608 sign,base %O A367608 1,1 %A A367608 _N. J. A. Sloane_, Dec 11 2023