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).

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.

Links

Table of n, a(n) for n=0..47.

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 * A043503 A202311 A319011

Adjacent sequences: A066346 A066347 A066348 * A066350 A066351 A066352

Keyword

base,easy,nonn,nice

Author

Evans A Criswell (criswell(AT)itsc.uah.edu), Dec 19 2001

Status

approved