A336944 Numbers k that have at least two different representations as the product of a number and of its decimal digits.
0, 192, 648, 819, 1197, 1536, 4872, 4977, 5976, 7056, 9968, 13608, 20448, 21168, 22176, 22428, 22752, 32040, 33984, 35424, 36864, 37692, 38736, 59778, 64152, 77600, 89928, 96912, 112833, 112896, 113148, 116352, 116736, 120384, 120708, 146412, 154752, 156288, 192888
Offset: 1
Examples
192 = 24 * (2*4) = 32 * (3*2). 549504 = 1696 * (1*6*9*6) = 2862 * (2*8*6*2) = 3392 * (3*3*9*2) = 3816 * (3*8*1*6). 1798848 = 6246 * (6*2*4*6) = 12492 * (1*2*4*9*2) = 33312 * (3*3*3*1*2).
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..10000 (n = 1..500 from Seiichi Manyama)
Programs
-
Mathematica
digprod[n_] := n * Times @@ IntegerDigits[n]; seqQ[0] = True; seqQ[n_] := DivisorSum[n, Boole[digprod[#] == n] &] > 1; Select[Range[0, 2 * 10^5], seqQ] (* Amiram Eldar, Aug 08 2020 *) Take[Select[Tally[Table[n*Times@@IntegerDigits[n],{n,30000}]],#[[2]]>1&][[;;,1]]//Sort,40] (* Harvey P. Dale, Apr 13 2025 *)
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