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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
1, 2, 3, 9, 10, 18, 19, 81, 90, 162, 171, 729, 810, 1458, 1539, 6561, 7290, 13122, 13851, 59049, 65610, 118098, 124659, 531441, 590490, 1062882, 1121931, 4782969, 5314410, 9565938, 10097379, 43046721, 47829690, 86093442, 90876411, 387420489, 430467210 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Base 9 analog of A278742.

LINKS

Colin Barker, Table of n, a(n) for n = 1..1000

N. J. A. Sloane, Illustration of initial terms

Index entries for linear recurrences with constant coefficients, signature (0,0,0,9).

FORMULA

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

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

PROG

(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

CROSSREFS

Cf. A278742, A278743, A280051, A280052.

See A281366 for these numbers written in base 9.

Sequence in context: A030743 A098020 A047358 * A003140 A057234 A109636

Adjacent sequences:  A280728 A280729 A280730 * A280732 A280733 A280734

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane, Jan 09 2017

STATUS

approved

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Last modified August 14 04:13 EDT 2020. Contains 336477 sequences. (Running on oeis4.)