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A082741
Numbers that have digits consisting only of line segments or both line segments and curves (base 10 digits are 1, 2, 4, 5, 7).
5
1, 2, 4, 5, 7, 11, 12, 14, 15, 17, 21, 22, 24, 25, 27, 41, 42, 44, 45, 47, 51, 52, 54, 55, 57, 71, 72, 74, 75, 77, 111, 112, 114, 115, 117, 121, 122, 124, 125, 127, 141, 142, 144, 145, 147, 151, 152, 154, 155, 157, 171, 172, 174, 175, 177, 211, 212, 214, 215, 217, 221
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.
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
Cf. A028373 (line-segment digits 1, 4, 7 only), A028374 (digits with curves or both curves and line segments), A072960 (curved digits 0, 3, 6, 8, 9 only).
Sequence in context: A145734 A349729 A027936 * A288349 A099522 A255850
KEYWORD
base,nonn,easy
AUTHOR
Rick L. Shepherd, May 21 2003
STATUS
approved