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).

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.

Links

Table of n, a(n) for n=0..50.

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

Adjacent sequences: A066798 A066799 A066800 * A066802 A066803 A066804

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