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A004492 Tersum n + 3. 0
3, 4, 5, 6, 7, 8, 0, 1, 2, 12, 13, 14, 15, 16, 17, 9, 10, 11, 21, 22, 23, 24, 25, 26, 18, 19, 20, 30, 31, 32, 33, 34, 35, 27, 28, 29, 39, 40, 41, 42, 43, 44, 36, 37, 38, 48, 49, 50, 51, 52, 53, 45, 46, 47, 57, 58, 59, 60 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..57.

Index entries for linear recurrences with constant coefficients, signature (2,-1,-1,2,-1,-1,2,-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) = -7 + Sum_{k=0..n} (1/36)*(-35*(k mod 9) + ((k+1) mod 9) - 35*((k+2) mod 9) + 37*((k+3) mod 9) + ((k+4) mod 9) + ((k+5) mod 9) + ((k+6) mod 9) + ((k+7) mod 9) + 37*((k+8) mod 9)), with n >= 0. - Paolo P. Lava, Dec 03 2007

G.f.: (3 - 2*x + 3*x^3 - 2*x^4 - 6*x^6 + 7*x^7)/((-1+x)^2*(1+x^3+x^6)). - Jinyuan Wang, Mar 10 2020

CROSSREFS

Sequence in context: A121151 A088243 A154660 * A333914 A140255 A050270

Adjacent sequences:  A004489 A004490 A004491 * A004493 A004494 A004495

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified April 10 18:04 EDT 2021. Contains 342852 sequences. (Running on oeis4.)