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 A004500 Tersum n + 11. 0
 11, 9, 10, 14, 12, 13, 17, 15, 16, 20, 18, 19, 23, 21, 22, 26, 24, 25, 2, 0, 1, 5, 3, 4, 8, 6, 7, 38, 36, 37, 41, 39, 40, 44, 42, 43, 47, 45, 46, 50, 48, 49, 53, 51, 52, 29, 27, 28, 32, 30, 31, 35, 33, 34, 65, 63, 64, 68, 66, 67, 71, 69, 70, 74, 72, 73, 77, 75 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1,0,0,0,0,-1,1,0,1,-1,0,0,0,0,-1,1,0,1,-1). FORMULA Tersum m + n: write m and n in base 3 and add mod 3 with no carries, e.g. 5 + 8 = "21" + "22" = "10" = 1. a(n) = A004489(n, 11). - Michel Marcus, Nov 09 2021 G.f.: (20*x^21+x^20-2*x^19-16*x^18-7*x^12+x^11-2*x^10+11*x^9-7*x^3+x^2-2*x+11) / ((x^2+x+1)*(x^18+x^9+1)*(x-1)^2). - Alois P. Heinz, Nov 09 2021 PROG (Python) def a(n):     k, pow3, m = 0, 1, 11     while n + m > 0:         n, rn = divmod(n, 3)         m, rm = divmod(m, 3)         k, pow3 = k + pow3*((rn+rm)%3), pow3*3     return k print([a(n) for n in range(58)]) # Michael S. Branicky, Nov 09 2021 CROSSREFS Cf. A004489. Sequence in context: A299972 A334275 A090075 * A342162 A337227 A254716 Adjacent sequences:  A004497 A004498 A004499 * A004501 A004502 A004503 KEYWORD nonn,base,easy AUTHOR STATUS approved

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Last modified January 19 00:22 EST 2022. Contains 350464 sequences. (Running on oeis4.)