OFFSET
1,1
COMMENTS
This sequence is a primitive sequence of A299690 because terms of that sequence can be found using this; permuting digits of terms of this sequence gives terms in A299690.
This sequence is also a primitive sequence to A318275 as prepending 0 or more ones to terms in this sequence gives terms in A318275.
This sequence is finite because it's a subsequence of the finite sequence A299690.
LINKS
David A. Corneth, Table of n, a(n) for n = 1..12413
MATHEMATICA
Select[Range[333], And[FreeQ[IntegerDigits@ #, 1], FixedPoint[Times @@ IntegerDigits@ # &, #] != 0, AllTrue[Differences@ IntegerDigits@ #, # >= 0 &]] &] (* Michael De Vlieger, Aug 25 2018 *)
PROG
(PARI) mdr(n)=n = fromdigits(n); while(n>9, n=factorback(digits(n))); n \\ from Charles R Greathouse IV at A299690.
uptoQdigits(n) = {my(res = List()); for(i = 1, n, forvec(x = vector(i, j, [2, 9]), c = mdr(x); if(c != 0, listput(res, fromdigits(x))), 1)); res} \\ David A. Corneth, Dec 31 2018
CROSSREFS
KEYWORD
AUTHOR
David A. Corneth, Aug 23 2018
EXTENSIONS
Data corrected by David A. Corneth, Dec 31 2018
STATUS
approved