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A066801
A self-generating sequence: let S = {}, a(0) = 333; for n >= 1, factorize a(n-1), arrange prime factors in increasing order and append their digits to S; then a(n) is the 3-digit number formed from terms 3n, 3n+1, 3n+2 of S. Leading zeros are omitted from a(n).
1
333, 735, 772, 219, 337, 333, 733, 377, 331, 329, 331, 747, 331, 338, 333, 121, 313, 333, 711, 113, 133, 337, 337, 911, 371, 933, 733, 791, 175, 333, 117, 337, 113, 557, 333, 733, 133, 371, 135, 573, 337, 733, 719, 753, 333, 531, 913, 377, 337, 193, 251
OFFSET
0,1
COMMENTS
333 is the unique 3-digit starting value that produces nontrivial sequences. This is one of the two possible continuations if one starts with 333. For the other see A066349.
EXAMPLE
The factorizations of the first few terms are 3*3*37, 3*5*7*7, 2*2*193, 3*73, 337, ... Thus S = [3,3,3,7,3,5,7,7,2,...] and grouping these in sets of three we recover the sequence.
CROSSREFS
Cf. A066349.
Sequence in context: A248062 A056089 A227228 * A066349 A372186 A043503
KEYWORD
base,easy,nice,nonn
AUTHOR
Evans A Criswell (criswell(AT)itsc.uah.edu), Dec 20 2001
EXTENSIONS
More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Jul 03 2003
STATUS
approved