A217556 Terms as well as ending/starting digits are of alternating parity; this is the lexicographically earliest injective sequence with this property.

1, 2, 3, 4, 5, 6, 7, 8, 9, 20, 11, 22, 13, 24, 15, 26, 17, 28, 19, 40, 31, 42, 33, 44, 35, 46, 37, 48, 39, 60, 51, 62, 53, 64, 55, 66, 57, 68, 59, 80, 71, 82, 73, 84, 75, 86, 77, 88, 79, 200, 91, 202, 93, 204, 95, 206, 97, 208, 99, 210, 101, 212, 103, 214, 105, 216, 107, 218, 109

Offset

1,2

Links

Table of n, a(n) for n=1..69.

E. Angelini, Odd/even: integers and digits alternate, SeqFan mailing list, Oct 06 2012

Prog

(PARI) A217556(n, show=0, a=1, u)={for( i=2, n, u+=1<<a; show & print1(a", "); for(t=1, 9e9, bittest(u, t) & next; bittest(t+a, 0) || next; !bittest(a%10 + t\10^(#Str(t)-1), 0) & (t+=10^(#Str(t)-1)-1) & next; a=t; break )); a}  \\ - M. F. Hasler, Oct 06 2012

Crossrefs

A simplified variant of A217555.

See also A217559, A217560, where "parity" is replaced by "primality".

Sequence in context: A345142 A275775 A358129 * A249873 A102491 A111706

Adjacent sequences: A217553 A217554 A217555 * A217557 A217558 A217559

Keyword

nonn,base

Author

Eric Angelini and M. F. Hasler, Oct 06 2012

Status

approved