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A034050 Numbers with multiplicative digital root value 3. 14
3, 13, 31, 113, 131, 311, 1113, 1131, 1311, 3111, 11113, 11131, 11311, 13111, 31111, 111113, 111131, 111311, 113111, 131111, 311111, 1111113, 1111131, 1111311, 1113111, 1131111, 1311111, 3111111, 11111113, 11111131, 11111311, 11113111 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers with one 3, and zero or more 1s. - Daniel Forgues, Oct 09 2011

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Multiplicative Digital Root

Index entries for 10-automatic sequences.

FORMULA

There are n(n+1)/2 members up to 10^n, so a(n) is about 10^sqrt(2n).

a(m*(m-1)/2+j+1) = (10^m-1)/9 + 2*10^j for 0 <= j < m. - Robert Israel, Sep 27 2016

MAPLE

seq(seq((10^m-1)/9 + 2*10^j, j=0..m-1), m=1..10); # Robert Israel, Sep 27 2016

MATHEMATICA

Sort[Flatten[Table[FromDigits/@Permutations[Join[{3}, PadRight[{}, n, 1]]], {n, 0, 8}]]] (* Harvey P. Dale, Jul 16 2012 *)

CROSSREFS

Cf. A031347.

Cf. A034048, A002275, A034049, A034050, A034051, A034052, A034053, A034054, A034055, A034056 (numbers having multiplicative digital roots 0-9).

Sequence in context: A058264 A242905 A213970 * A107689 A154834 A159047

Adjacent sequences:  A034047 A034048 A034049 * A034051 A034052 A034053

KEYWORD

nonn,base,easy

AUTHOR

Patrick De Geest, Sep 15 1998

STATUS

approved

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Last modified May 21 23:35 EDT 2019. Contains 323470 sequences. (Running on oeis4.)