# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a367609 Showing 1-1 of 1 %I A367609 #13 Feb 07 2024 13:21:43 %S A367609 11,21,1,-1,21,2,11,21,1,11,22,1,11,22,1,12,22,2,12,21,2,-1,21,2,11, %T A367609 21,1,11,21,1,11,21,1,11,21,1,11,21,1,11,21,1,11,21,1,11,22,1,11,22,1, %U A367609 12,22,2,12,22,2,12,22,2,12,22,2,12,22,2,12,22,2,12,22,2,12,21,2,-1,21,2,11,21,1,11,21,1,11,21,1,11,21,1,11,21,1,11,21,1,11,21,1,11 %N A367609 Comma-number associated with A367607(n), and written in base 3, or -1 if A367607(n) = -1. %C A367609 This is a base-3 analog of A367339. %H A367609 Michael S. Branicky, Table of n, a(n) for n = 1..10000 %H A367609 Eric Angelini, Michael S. Branicky, Giovanni Resta, N. J. A. Sloane, and David W. Wilson, The Comma Sequence: A Simple Sequence With Bizarre Properties, arXiv:2401.14346, Youtube %o A367609 (Python) %o A367609 from sympy.ntheory.factor_ import digits %o A367609 def a(n): %o A367609 b = n + 3*(n%3) %o A367609 return next((int("".join(map(str, digits(b+y-n, 3)[1:]))) for y in [1, 2] if digits(b+y, 3)[1] == y), -1) %o A367609 print([a(n) for n in range(1, 101)]) # _Michael S. Branicky_, Dec 11 2023 %Y A367609 Cf. A121085, A367339, A367355, A367356, A367606-A367608. %K A367609 sign,base %O A367609 1,1 %A A367609 _N. J. A. Sloane_, Dec 11 2023 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE