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

Author

Amarnath Murthy, Nov 10 2005

Keywords

• base
• nonn

Examples

			96 is a term as 96 = 2^5*3 and contains digits 9,6 both composite. 96 is a member of A002473.
		

Crossrefs

Intersection of A001744 and A002473.

Cf. A113623.

Programs

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