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A066349
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, 775, 531, 335, 956, 722, 239, 219, 192, 393, 732, 222, 223, 313, 122, 361, 233, 722, 331, 326, 119, 192, 332, 191, 933, 121, 637, 172, 222, 223, 228, 319, 133, 111, 111, 771, 322, 432, 337, 223, 223, 191, 129, 719, 337, 337, 325
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 A066801.
EXAMPLE
The factorizations of the first few terms are 3*3*37, 3*5*7*7, 5*5*31, 3*3*59, 5*67, 2*2*239, ... Thus S = [3,3,3,7,3,5,7,7,5,...] and grouping these in sets of three we recover the sequence.
CROSSREFS
Sequence in context: A056089 A227228 A066801 * A372186 A043503 A202311
KEYWORD
base,easy,nonn,nice
AUTHOR
Evans A Criswell (criswell(AT)itsc.uah.edu), Dec 19 2001
STATUS
approved