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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
OFFSET
1,1
COMMENTS
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).
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.
Inspired by Eric Angelini's posting to Seq Fan mailing list, Jul 23, 2007.
LINKS
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: A171903 A072433 A372301 * A045298 A304951 A316619
KEYWORD
nonn,base
AUTHOR
Klaus Brockhaus, Sep 19 2007
STATUS
approved