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A239722
Numbers that end in (..., 384, 384, 384, ...) under the rule: next term = product of the last four digits in the sequence so far.
5
12, 13, 14, 17, 19, 21, 24, 28, 38, 42, 61, 62, 68, 69, 112, 113, 114, 117, 119, 121, 122, 123, 126, 128, 129, 131, 133, 134, 136, 137, 142, 143, 144, 148, 162, 163, 173, 177, 179, 182, 184, 192, 197, 199, 211, 212, 217, 218, 221, 224, 228, 231, 242, 244, 249, 267, 268, 271, 274, 278, 281, 282, 284, 287, 294, 299, 311, 312, 321
OFFSET
1,1
COMMENTS
Additional rule: If there are fewer than k=4 digits in the sequence so far, then it is "extended to the left" with the first digit (i.e., that digit is repeated as often as necessary).
Apart from the trivial cycles (0) (cf. A239616) and (1) and the cycle (384) considered here, the rule also allows the "constant" cycle (175), cf. A239721.
PROG
(PARI) is_A239722(n) = A238984(99, n, 4)==384 \\ The "99" here should be large enough to reach the cycle (384), for small initial values n. It might be necessary to increase this value in other cases.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
M. F. Hasler, Aug 01 2014
STATUS
approved