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 A190220 Numbers all of whose divisors are numbers whose decimal digits are in nonincreasing order. 3
 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 20, 21, 22, 31, 33, 40, 41, 43, 44, 53, 55, 61, 62, 63, 66, 71, 73, 77, 82, 83, 86, 88, 93, 97, 99, 110, 211, 220, 311, 331, 421, 422, 431, 433, 440, 443, 511, 521, 541, 622, 631, 633, 641, 643, 653, 661, 662, 733, 743, 751 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Subset of A009996. Superset of A028867, A190219 and A190217. LINKS Nathaniel Johnston, Table of n, a(n) for n = 1..500 EXAMPLE Number 110 is in sequence because all divisors of 110 (1, 2, 5, 10, 11, 22, 55, 110) are numbers whose decimal digits are in nonincreasing order. MAPLE with(numtheory): A190220 := 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(A190220(n), n=1..64); # Nathaniel Johnston, May 14 2011 CROSSREFS Sequence in context: A032907 A130576 A334145 * A113586 A061362 A096091 Adjacent sequences:  A190217 A190218 A190219 * A190221 A190222 A190223 KEYWORD nonn,base AUTHOR Jaroslav Krizek, May 06 2011 STATUS approved

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Last modified September 22 09:32 EDT 2020. Contains 337289 sequences. (Running on oeis4.)