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 A280731 Lexicographically least strictly increasing sequence such that, for any n>0, Sum_{k=1..n} a(k) can be computed without carries in base 9 (the numbers are written in base 10). 2

%I

%S 1,2,3,9,10,18,19,81,90,162,171,729,810,1458,1539,6561,7290,13122,

%T 13851,59049,65610,118098,124659,531441,590490,1062882,1121931,

%U 4782969,5314410,9565938,10097379,43046721,47829690,86093442,90876411,387420489,430467210

%N Lexicographically least strictly increasing sequence such that, for any n>0, Sum_{k=1..n} a(k) can be computed without carries in base 9 (the numbers are written in base 10).

%C Base 9 analog of A278742.

%H Colin Barker, <a href="/A280731/b280731.txt">Table of n, a(n) for n = 1..1000</a>

%H N. J. A. Sloane, <a href="/A280731/a280731.jpg">Illustration of initial terms</a>

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,9).

%F For k>7, a(k+4) = 9*a(k).

%F G.f.: x*(1 + 2*x + 3*x^2 + 9*x^3 + x^4 - 8*x^6) / ((1 - 3*x^2)*(1 + 3*x^2)). - _Colin Barker_, Jan 10 2017

%o (PARI) Vec(x*(1 + 2*x + 3*x^2 + 9*x^3 + x^4 - 8*x^6) / ((1 - 3*x^2)*(1 + 3*x^2)) + O(x^50)) \\ _Colin Barker_, Jan 10 2017

%Y Cf. A278742, A278743, A280051, A280052.

%Y See A281366 for these numbers written in base 9.

%K nonn,base,easy

%O 1,2

%A _N. J. A. Sloane_, Jan 09 2017

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Last modified September 18 03:39 EDT 2020. Contains 337164 sequences. (Running on oeis4.)