

A133650


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


3



99, 111, 122, 123, 132, 142, 152, 162, 172, 182, 192, 211, 212, 214, 215, 216, 217, 218, 219, 220, 221, 231, 232, 233, 234, 243, 253, 263, 273, 283, 293, 311, 312, 313, 321, 322, 323, 325, 326, 327, 328, 329, 330, 331, 332, 342, 343, 344, 345, 354, 364, 374
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OFFSET

1,1


COMMENTS

Nth Early bird number A116700(n) is in the sequence if it occurs in the concatenation of the first n1 early bird numbers, A116700(1), ..., A116700(n1).
With A116700 as early bird numbers of order 1, this can be generalized to define early bird numbers of order k for k > 1: Nth Early bird number of order k1 is an early bird number of order k if it occurs in the concatenation of the first n1 early bird numbers of order k1.
Inspired by Eric Angelini's posting to Seq Fan mailing list, Jul 23, 2007.


LINKS

Klaus Brockhaus, Table of n, a(n) for n = 1..1000


EXAMPLE

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


PROG

(JBASIC) Program works for order >= 1; set maxterm >= A133652(order).
order = 2
maxterm = 374 : dim seq(maxterm), early(maxterm)
for i = 1 to maxterm : seq(i) = i : next
for k = 1 to order
concatenation$ = "" : n = 0
for j = 1 to maxterm
term = seq(j) : string$ = str$(term)
if instr(concatenation$, string$) > 0 then n = n+1 : early(n) = term
concatenation$ = concatenation$ + string$
next j
maxterm = n : redim seq(maxterm)
for i = 1 to maxterm : seq(i) = early(i) : next
redim early(maxterm)
next k
print "early bird numbers of order "; order
for i = 1 to maxterm : print seq(i); ", "; : next


CROSSREFS

Cf. A116700 (early bird numbers), A133651 (early bird numbers of order 3), A133652 (least early bird number of order n).
Sequence in context: A171904 A171903 A072433 * A045298 A304951 A316619
Adjacent sequences: A133647 A133648 A133649 * A133651 A133652 A133653


KEYWORD

nonn,base


AUTHOR

Klaus Brockhaus, Sep 19 2007


STATUS

approved



