A113624 7-smooth numbers containing only composite digits (0,4,6,8,9).
4, 6, 8, 9, 40, 48, 49, 60, 64, 80, 84, 90, 96, 98, 400, 448, 480, 486, 490, 600, 640, 648, 686, 800, 840, 864, 896, 900, 960, 980, 4000, 4096, 4480, 4608, 4800, 4860, 4900, 6000, 6048, 6400, 6480, 6804, 6860, 8000, 8064, 8400, 8640, 8960, 9000, 9408, 9600
Offset: 1
Examples
96 is a term as 96 = 2^5*3 and contains digits 9,6 both composite. 96 is a member of A002473.
Programs
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Mathematica
Select[Select[Range[2, 10000], FactorInteger[ # ][[ -1]][[1]] <= 7 &], DigitCount[ # ][[1]]+DigitCount[ # ][[2]]+DigitCount[ # ][[3]]+DigitCount[ # ][[5]]+ DigitCount[ # ][[7]] == 0 &] (* Stefan Steinerberger, Apr 11 2006 *)
Extensions
More terms from Stefan Steinerberger, Apr 11 2006
Name corrected and offset changed by Andrew Howroyd, Sep 17 2024