

A275775


The pair (a(n), a(n+1)) uses only one odd digit.


2



1, 2, 3, 4, 5, 6, 7, 8, 9, 20, 10, 22, 12, 24, 14, 26, 16, 28, 18, 40, 21, 42, 23, 44, 25, 46, 27, 48, 29, 60, 30, 62, 32, 64, 34, 66, 36, 68, 38, 80, 41, 82, 43, 84, 45, 86, 47, 88, 49, 200, 50, 202, 52, 204, 54, 206, 56, 208, 58, 220, 61, 222, 63, 224, 65, 226, 67, 228, 69, 240, 70, 242, 72, 244, 74, 246, 76, 248, 78, 260, 81, 262, 83, 264, 85, 266, 87, 268
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OFFSET

1,2


COMMENTS

The sequence starts with a(1) = 1 and is always extended with the smallest integer not yet used that doesn't lead to a contradiction.


LINKS



EXAMPLE

The pair (1,2) uses only one odd digit (1);
the pair (2,3) uses only one odd digit (3);
the pair (3,4) uses only one odd digit (3);
the pair (4,5) uses only one odd digit (5);
the pair (5,6) uses only one odd digit (5);
the pair (6,7) uses only one odd digit (7);
the pair (7,8) uses only one odd digit (7);
the pair (8,9) uses only one odd digit (9);
the pair (9,20) uses only one odd digit (9);
the pair (20,10) uses only one odd digit (1);
the pair (10,22) uses only one odd digit (1);
etc.


MAPLE

a:= 0: b:= 0: Res:= NULL:
for i from 1 to 100 do
for t from a+1 while nops(select(type, convert(t, base, 10), odd))<> 1 do
od;
a:= t;
for t from b+1 while nops(select(type, convert(t, base, 10), odd))>0 do
od;
b:= t;
Res:= Res, a, b;
od:


CROSSREFS



KEYWORD

nonn,base


AUTHOR



STATUS

approved



