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A133650 Early early bird numbers (early bird numbers of order 2). 3

%I

%S 99,111,122,123,132,142,152,162,172,182,192,211,212,214,215,216,217,

%T 218,219,220,221,231,232,233,234,243,253,263,273,283,293,311,312,313,

%U 321,322,323,325,326,327,328,329,330,331,332,342,343,344,345,354,364,374

%N Early early bird numbers (early bird numbers of order 2).

%C N-th Early bird number A116700(n) is in the sequence if it occurs in the concatenation of the first n-1 early bird numbers, A116700(1), ..., A116700(n-1).

%C With A116700 as early bird numbers of order 1, this can be generalized to define early bird numbers of order k for k > 1: N-th Early bird number of order k-1 is an early bird number of order k if it occurs in the concatenation of the first n-1 early bird numbers of order k-1.

%C Inspired by Eric Angelini's posting to Seq Fan mailing list, Jul 23, 2007.

%H Klaus Brockhaus, <a href="/A133650/b133650.txt">Table of n, a(n) for n = 1..1000</a>

%e A116700(45) = 99 occurs in the concatenation 1221233132344142434551525354566162636465677172737475767881828384858687899192939495969798 of A116700(1), ..., A116700(44). Hence 99 is an early bird number of order 2.

%o (JBASIC) Program works for order >= 1; set maxterm >= A133652(order).

%o order = 2

%o maxterm = 374 : dim seq(maxterm), early(maxterm)

%o for i = 1 to maxterm : seq(i) = i : next

%o for k = 1 to order

%o concatenation$ = "" : n = 0

%o for j = 1 to maxterm

%o term = seq(j) : string$ = str$(term)

%o if instr(concatenation$, string$) > 0 then n = n+1 : early(n) = term

%o concatenation$ = concatenation$ + string$

%o next j

%o maxterm = n : redim seq(maxterm)

%o for i = 1 to maxterm : seq(i) = early(i) : next

%o redim early(maxterm)

%o next k

%o print "early bird numbers of order "; order

%o for i = 1 to maxterm : print seq(i); ","; : next

%Y Cf. A116700 (early bird numbers), A133651 (early bird numbers of order 3), A133652 (least early bird number of order n).

%K nonn,base

%O 1,1

%A _Klaus Brockhaus_, Sep 19 2007

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Last modified February 16 21:37 EST 2020. Contains 331975 sequences. (Running on oeis4.)