OFFSET
1,2
COMMENTS
This sequence allows the digits 2 and 5, formed from combinations of line segments and curves; the subsequence A028373 does not.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000
MAPLE
a:= proc(n) local d, i, m, r; m:=n; r:=0;
for i from 0 while m>0 do
d:= irem(m, 5, 'm');
if d=0 then d:=5; m:=m-1 fi;
r:= r+10^i*[1, 2, 4, 5, 7][d]
od: r
end:
seq(a(n), n=1..100); # Alois P. Heinz, May 25 2014
MATHEMATICA
Table[FromDigits/@Tuples[{1, 2, 4, 5, 7}, n], {n, 3}]//Flatten (* Harvey P. Dale, Apr 17 2022 *)
CROSSREFS
KEYWORD
base,nonn,easy
AUTHOR
Rick L. Shepherd, May 21 2003
STATUS
approved