A299973 - OEIS

A299973

Lexicographic first sequence of positive integers such that a(n) + a(n+1) has a digit 3, and no term occurs twice.

1, 2, 11, 12, 18, 5, 8, 15, 16, 7, 6, 17, 13, 10, 3, 20, 14, 9, 4, 19, 24, 29, 34, 39, 44, 49, 54, 59, 64, 66, 27, 26, 37, 36, 47, 46, 57, 56, 67, 63, 30, 23, 40, 33, 50, 43, 60, 53, 70, 61, 22

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OFFSET

1,2

COMMENTS

A permutation of the positive integers.

LINKS

Table of n, a(n) for n=1..51.

PROG

(PARI) a(n, f=1, d=3, 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. A299983 (analog with nonnegative terms), A299957 (analog with digit 1), A299970..A299979 (digit 0..9).

Sequence in context: A216213 A160948 A373942 * A136971 A061677 A110126

Adjacent sequences: A299970 A299971 A299972 * A299974 A299975 A299976

KEYWORD

nonn,base

AUTHOR

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

STATUS

approved