A299984 Lexicographic first sequence of nonnegative integers such that a(n) + a(n+1) has a digit 4, and no term occurs twice.

0, 4, 10, 14, 20, 21, 3, 1, 13, 11, 23, 17, 7, 27, 15, 9, 5, 19, 22, 2, 12, 28, 6, 8, 16, 18, 24, 25, 29, 35, 39, 45, 49, 55, 59, 65, 69, 71, 33, 31, 43, 41, 53, 51, 63, 61, 73, 67, 37, 47, 57, 77, 64, 30, 34, 40, 44, 50, 54, 60, 74, 66, 38, 26, 48, 36, 58, 46, 68, 56, 78, 62, 32, 42, 52, 72, 70, 75, 79, 85, 89, 95, 99, 105, 109, 115, 119, 121, 83

Offset

0,2

Comments

A permutation of the nonnegative integers.

Links

Table of n, a(n) for n=0..88.

Prog

(PARI) a(n, f=1, d=4, a=0, u=[a])={for(n=1, 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. A299974 (analog with positive terms), A299957 (analog with digit 1), A299970, A299982, ..., A299988, A299969 (digit 0, 2, ..., 8, 9).

Sequence in context: A310404 A310405 A310406 * A310407 A310408 A310409

Adjacent sequences: A299981 A299982 A299983 * A299985 A299986 A299987

Keyword

nonn,base

Author

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

Status

approved