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 A374363 #9 Jul 09 2024 02:21:41 %S A374363 0,1,1,3,4,4,3,4,4,9,10,10,12,13,13,12,13,13,9,10,10,12,13,13,12,13, %T A374363 13,27,28,28,30,31,31,30,31,31,36,37,37,39,40,40,39,40,40,36,37,37,39, %U A374363 40,40,39,40,40,27,28,28,30,31,31,30,31,31,36,37,37,39,40 %N A374363 a(n) is the greatest term t <= n of A005836 such that n - t also belongs to A005836. %C A374363 To compute a(n): in the ternary expansion of n, 2's by 1's. %H A374363 Rémy Sigrist, <a href="/A374363/b374363.txt">Table of n, a(n) for n = 0..6560</a> %F A374363 a(n) = T(n, A120880(k)-1). %F A374363 a(n) = n - A374362(n). %F A374363 a(n) <= n with equality iff n belongs to A005836. %F A374363 a(n) = A005836(1+A289831(n)). %e A374363 The first terms, in decimal and in ternary, are: %e A374363 n a(n) ter(n) ter(a(n)) %e A374363 -- ---- ------ --------- %e A374363 0 0 0 0 %e A374363 1 1 1 1 %e A374363 2 1 2 1 %e A374363 3 3 10 10 %e A374363 4 4 11 11 %e A374363 5 4 12 11 %e A374363 6 3 20 10 %e A374363 7 4 21 11 %e A374363 8 4 22 11 %e A374363 9 9 100 100 %e A374363 10 10 101 101 %e A374363 11 10 102 101 %e A374363 12 12 110 110 %e A374363 13 13 111 111 %e A374363 14 13 112 111 %e A374363 15 12 120 110 %o A374363 (PARI) a(n) = fromdigits(apply(d -> [0, 1, 1][1+d], digits(n, 3)), 3) %Y A374363 Cf. A005836, A120880, A289831, A374361, A374362. %K A374363 nonn,base %O A374363 0,4 %A A374363 _Rémy Sigrist_, Jul 06 2024