A299972 Lexicographic first sequence of positive integers such that a(n) + a(n+1) has a digit 2, and no term occurs twice.

1, 11, 9, 3, 17, 4, 8, 12, 10, 2, 18, 5, 7, 13, 14, 6, 15, 27, 25, 37, 35, 47, 45, 57, 55, 65, 56, 16, 26, 36, 46, 66, 54, 28, 24, 38, 34, 48, 44, 58, 62, 20, 22, 30, 32, 40, 42, 50, 52, 60, 61, 21, 31, 41, 51, 69, 23, 19, 33, 29, 43, 39, 53, 49, 63, 59, 64, 68

Offset

1,2

Comments

A permutation of the positive integers.

Links

Table of n, a(n) for n=1..68.

Prog

(PARI) a(n, f=1, d=2, a=1, u=[a])={for(n=2, n, f&&if(f==1, print1(a", "), write(f, n-1, " "a)); for(k=u[1]+1, oo, setsearch(u, k)&&next; setsearch(Set(digits(a+k)), d)&&(a=k)&&break); u=setunion(u, [a]); u[2]==u[1]+1&&u=u[^1]); a}

Crossrefs

Cf. A299970 (analog with digit 0), A299957 (digit 1), A299973..A299979 (digit 3..9).

Sequence in context: A304699 A133236 A038322 * A334275 A090075 A004500

Adjacent sequences: A299969 A299970 A299971 * A299973 A299974 A299975

Keyword

nonn,base

Author

M. F. Hasler and Eric Angelini, Feb 22 2018

Status

approved