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A299974 Lexicographic first sequence of positive integers such that a(n) + a(n+1) has a digit 4, and no term occurs twice. 1
1, 3, 11, 13, 21, 19, 5, 9, 15, 25, 16, 8, 6, 18, 22, 2, 12, 28, 14, 10, 4, 20, 23, 17, 7, 27, 37, 47, 57, 67, 73, 31, 33, 41, 43, 51, 53, 61, 63, 71, 69, 35, 29, 45, 39, 55, 49, 65, 59, 75, 66, 38, 26, 48, 36, 58, 46, 68, 56, 78, 62, 32, 42, 52, 72, 70, 24, 30, 34, 40, 44, 50, 54, 60, 64, 76, 88, 86, 98, 96, 108, 106, 118, 116, 124, 80, 74, 90, 84 (list; graph; refs; listen; history; text; internal format)
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=4, 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. A299984 (analog with nonnegative terms), A299957 (analog with digit 1), A299971, A299972, ..., A299979 (digit 0, 2, ..., 9).

Sequence in context: A066594 A329761 A167612 * A262433 A116438 A191078

Adjacent sequences:  A299971 A299972 A299973 * A299975 A299976 A299977

KEYWORD

nonn,base

AUTHOR

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

STATUS

approved

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Last modified January 27 21:48 EST 2020. Contains 331297 sequences. (Running on oeis4.)