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 A189788 Base-10 lunar factorials: a(n) = (lunar) Product_{i=1..n} i. 1
 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 110, 1110, 11110, 111110, 1111110, 11111110, 111111110, 1111111110, 11111111110, 111111111100, 1111111111100, 11111111111100, 111111111111100, 1111111111111100, 11111111111111100, 111111111111111100, 1111111111111111100, 11111111111111111100, 111111111111111111100, 1111111111111111111000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS 0!, the empty product, equals 9 (the multiplicative identity) by convention. LINKS M. F. Hasler, Table of n, a(n) for n = 0..200 D. Applegate, M. LeBrun and N. J. A. Sloane, Dismal Arithmetic, arXiv:1107.1130 [math.NT], 2011. [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing] D. Applegate, M. LeBrun, N. J. A. Sloane, Dismal Arithmetic, J. Int. Seq. 14 (2011) # 11.9.8. EXAMPLE 4! = 1 X 2 X 3 X 4 = 1, where X is lunar multiplication, A087062. PROG (PARI) apply( A189788(n)=if(n>9, for(k=10, n-1, n=A087062(n, k)); n, 9^!n), [0..30]) \\ M. F. Hasler, Nov 15 2018 CROSSREFS Cf. A087062 (lunar product), A087019 (lunar squares). Sequence in context: A266557 A010534 A078297 * A264981 A113061 A284099 Adjacent sequences:  A189785 A189786 A189787 * A189789 A189790 A189791 KEYWORD nonn,base AUTHOR N. J. A. Sloane, May 23 2011 EXTENSIONS a(0) = 9 prepended and minor edits by M. F. Hasler, Nov 15 2018 STATUS approved

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Last modified January 23 22:26 EST 2019. Contains 319404 sequences. (Running on oeis4.)