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A268449 Last digit of a(n) + first digit of a(n+1) occurs as a substring in a(n); lexicographic first sequence with this property and no duplicates. 2
10, 100, 101, 90, 91, 80, 81, 70, 71, 60, 61, 50, 51, 40, 41, 30, 31, 20, 21, 102, 82, 62, 42, 200, 201, 103, 72, 52, 32, 104, 63, 300, 301, 210, 105, 53, 211, 106, 43, 107, 302, 108, 220, 221, 109, 110, 112, 92, 73, 400, 401, 310, 113, 83, 54, 114, 74, 311 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A permutation of the numbers of the form 10k+z, 0 <= z <= 9, k having a digit > z or a digit 1 followed by a digit < z.

Sequence suggested by Eric Angelini, first 500 terms independently computed by Jack Brennen, cf. link to SeqFan list.

LINKS

M. F. Hasler, Table of n, a(n) for n = 1..10000

E. Angelini, A sum visible in the 1st integer, and replies to this post, SeqFan list, Feb. 4, 2016.

PROG

EA(n, a=List(10), u=[0])={ my(isok(n)=vecmax(n=digits(n))>n[#n] || sum(i=1, #n-2, n[i]==1 && n[i+1]<n[#n])); for(n=1, n-1, u=setunion(u, [a[n]]); until( isok(u[1]+1) || !u[1]++ , while(#u>1&&u[2]==u[1]+1, u=u[^1])); ok=setintersect(apply(t->t-a[n]%10, Set(concat(ok=digits(a[n]), vector(#ok-1, i, ok[i+1]+ok[i]*10)))), [1..9]); for(k=u[1]+1, 9e9, setsearch(u, k) && next; isok(k) || next; setsearch(ok, digits(k)[1]) && listput(a, k) && break; k=digits(k); k=(k[1]+1)*10^(#k-1)-1)); Vec(a)}

CROSSREFS

Cf. A267759 (admissible numbers; range of this sequence).

Cf. A267760, A267761, A267762, A267771, A267772.

Sequence in context: A119589 A316915 A266798 * A289826 A309390 A323708

Adjacent sequences:  A268446 A268447 A268448 * A268450 A268451 A268452

KEYWORD

nonn,base,look

AUTHOR

M. F. Hasler, Feb 04 2016

STATUS

approved

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Last modified November 20 05:07 EST 2019. Contains 329323 sequences. (Running on oeis4.)