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A051809 Numbers with nonzero multiplicative digital root 7. 2
7, 17, 70, 71, 107, 117, 170, 171, 257, 275, 527, 572, 700, 701, 710, 711, 725, 752, 1007, 1017, 1070, 1071, 1107, 1117, 1170, 1171, 1257, 1275, 1527, 1572, 1700, 1701, 1710, 1711, 1725, 1752, 2057, 2075, 2157, 2175 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..40.

Index entries for 10-automatic sequences.

FORMULA

A051802^-1(7)

MATHEMATICA

Select[Range[2500], NestWhile[Times@@(IntegerDigits[#]/.(0->1))&, #, #>9&] == 7&] (* Harvey P. Dale, Jan 18 2019 *)

CROSSREFS

Part of histogram of A051802.

Sequence in context: A136192 A269239 A118431 * A254500 A242907 A034054

Adjacent sequences:  A051806 A051807 A051808 * A051810 A051811 A051812

KEYWORD

nonn,easy,base

AUTHOR

Dan Hoey, Dec 09 1999

STATUS

approved

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Last modified December 15 00:30 EST 2019. Contains 329988 sequences. (Running on oeis4.)