A299975 Lexicographic first sequence of positive integers such that a(n) + a(n+1) has a digit 5, and no term occurs twice.

1, 4, 11, 14, 21, 24, 26, 9, 6, 19, 16, 29, 22, 3, 2, 13, 12, 23, 27, 8, 7, 18, 17, 28, 25, 10, 5, 20, 15, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 76, 39, 36, 49, 46, 59, 56, 69, 66, 79, 71, 34, 31, 44, 41, 54, 51, 64, 61, 74, 77, 38, 37, 48, 47, 58, 57, 68, 67, 78, 72, 33, 32, 43, 42, 53, 52, 63, 62, 73, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125

Offset

1,2

Comments

A permutation of the positive integers.

Links

Table of n, a(n) for n=1..89.

Prog

(PARI) a(n, f=1, d=5, 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. A299985 (analog with nonnegative terms), A299957 (analog with digit 1), A299971, A299972, ..., A299979 (digit 0, 2, ..., 9).

Sequence in context: A204542 A247521 A285979 * A271508 A284323 A352403

Adjacent sequences: A299972 A299973 A299974 * A299976 A299977 A299978

Keyword

nonn,base

Author

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

Status

approved