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 A268869 Number of sequences in {1,...,n}^n with longest increasing subsequence of length two. 2
 1, 16, 175, 1771, 17906, 184920, 1958979, 21253375, 235401166, 2653427140, 30356604642, 351714783980, 4119532070980, 48708027030608, 580682498991627, 6973355148949335, 84286653134676230, 1024694093358751200, 12522664845237058050, 153762682169941498170 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 LINKS Alois P. Heinz, Table of n, a(n) for n = 2..900 FORMULA a(n) = A239295(n) - A088218(n) = A239295(n) - A001700(n-1). EXAMPLE a(2) = 1: 12. a(3) = 16: 112, 113, 121, 122, 131, 132, 133, 212, 213, 223, 231, 232, 233, 312, 313, 323. a(4) = 175: 1112, 1113, 1114, 1121, ..., 4414, 4423, 4424, 4434. CROSSREFS Column k=2 of A245667. Cf. A001700, A088218, A239295. Sequence in context: A187720 A017931 A021129 * A268459 A070030 A283278 Adjacent sequences: A268866 A268867 A268868 * A268870 A268871 A268872 KEYWORD nonn,easy AUTHOR Alois P. Heinz, Feb 15 2016 STATUS approved

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Last modified June 5 12:45 EDT 2023. Contains 363136 sequences. (Running on oeis4.)