A090652 Numbers all of whose prime factors end in 7.

7, 17, 37, 47, 49, 67, 97, 107, 119, 127, 137, 157, 167, 197, 227, 257, 259, 277, 289, 307, 317, 329, 337, 343, 347, 367, 397, 457, 467, 469, 487, 547, 557, 577, 587, 607, 617, 629, 647, 677, 679, 727, 749, 757, 787, 797, 799, 827, 833, 857, 877, 887, 889

Offset: 1

Author

Cino Hilliard, Dec 13 2003

Keywords

• easy
• nonn
• base

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..10000

Programs

Mathematica

Select[Range[1000],Union[Mod[Transpose[FactorInteger[#]][[1]],10]]=={7}&] (* Harvey P. Dale, May 28 2014 *)

PARI

numbers whose factors end in m endfactm(n,m) = { flag=0; for(x=2,n, y=factor(x); z=y[,1]; ln=length(z); for(j=1,ln, if(z[j]%10<>m,flag=0;break,flag=1) ); if(flag==1,print1(x",")) ) }