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A190219 Numbers all of whose divisors have decimal digits in strictly decreasing order. 2
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 21, 31, 40, 41, 43, 53, 61, 62, 63, 71, 73, 82, 83, 86, 93, 97, 421, 431, 521, 541, 631, 641, 643, 653, 743, 751, 761, 821, 842, 853, 862, 863, 941, 953, 961, 971, 983, 5431, 6421, 6521, 7321, 7541, 7621, 7643, 8431, 8521 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Sequence is finite. Last term a(104) = 98765431.

Subset of A009995 and A190220. Superset of A052014.

LINKS

Nathaniel Johnston, Table of n, a(n) for n = 1..104 (full sequence)

EXAMPLE

Number 93 is in sequence because all divisors of 93 (1, 3, 31, 93) are numbers whose decimal digits are in strictly decreasing order.

MAPLE

with(numtheory): A190219 := proc(n) option remember: local d, dd, i, j, k, m, poten: if(n=1)then return 1: fi: for k from procname(n-1)+1 do d:=divisors(k): poten:=1: for i from 1 to nops(d) do m:=-1: dd:=convert(d[i], base, 10): for j from 1 to nops(dd) do if(m<dd[j])then m:=dd[j]: else poten:=0: break: fi: od: if(poten=0)then break:fi: od: if(poten=1)then return k: fi: od: end: seq(A190219(n), n=1..60); # Nathaniel Johnston, May 06 2011

CROSSREFS

Sequence in context: A032865 A032889 A009995 * A038367 A214958 A161350

Adjacent sequences:  A190216 A190217 A190218 * A190220 A190221 A190222

KEYWORD

nonn,fini,full,base,changed

AUTHOR

Jaroslav Krizek, May 06 2011

STATUS

approved

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Last modified February 20 08:44 EST 2019. Contains 320325 sequences. (Running on oeis4.)