A061825 Multiples of 7 containing only odd digits.

7, 35, 77, 91, 119, 133, 175, 315, 357, 371, 399, 511, 539, 553, 595, 735, 777, 791, 917, 931, 959, 973, 1113, 1155, 1197, 1337, 1351, 1379, 1393, 1519, 1533, 1575, 1715, 1757, 1771, 1799, 1911, 1939, 1953, 1995, 3115, 3157, 3171, 3199, 3311, 3339

Offset: 1

Author

Amarnath Murthy, May 28 2001

Keywords

• nonn
• base
• easy

Examples

			315 = 7*45 is a term as it contains only odd digits.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000
• Index entries for 10-automatic sequences.

Crossrefs

Subsequence of A008589.

Cf. A061826.

Programs

Maple

R:= NULL:
for d from 1 to 4 do
  for n from 5^d to 2*5^d-1 do
    L:= map(t -> 2*t+1,convert(n,base,5)[1..d]);
    x:= add(L[i]*10^(i-1),i=1..nops(L));
    if x mod 7 = 0 then
      R:= R, x;
    fi;
od od:
R; # Robert Israel, Nov 02 2019

Mathematica

Select[7*Range[500], Count[IntegerDigits[#], ?EvenQ]==0&] (* _Harvey P. Dale, Jun 13 2011 *)

PARI

is(n)=n%7==0 && #setintersect(Set(digits(n)), [0,2,4,6,8])==0 \\ Charles R Greathouse IV, Feb 15 2017

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 30 2001