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 A091315 Number of orbits of length n under the map whose periodic points are counted by A061684. 0
 1, 2, 21, 402, 13805, 761154, 62523664, 7237970648, 1132600004910, 231900134422880, 60528794385067778, 19713593779259862624, 7869483395065035685162, 3792402572391137423764584 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Old name was: A061684 appears to count the periodic points for a certain map. If so, then this is the sequence of the numbers of orbits of length n. LINKS Y. Puri and T. Ward, Arithmetic and growth of periodic orbits, J. Integer Seqs., Vol. 4 (2001), #01.2.1. J.-M. Sixdeniers, K. A. Penson and A. I. Solomon, Extended Bell and Stirling Numbers From Hypergeometric Exponentiation, J. Integer Seqs. Vol. 4 (2001), #01.1.4. Thomas Ward, Exactly realizable sequences. [local copy]. FORMULA If b(n) is the (n+1)th term in A061684, then a(n) = (1/n)*Sum_{d|n}mu(d)b(n/d). EXAMPLE The sequence A061684 begins 1,1,5,64,1613, so a(3)=(b(3)-b(1))/3=21. CROSSREFS Cf. A061684. Sequence in context: A216281 A263625 A245686 * A087546 A090729 A090310 Adjacent sequences:  A091312 A091313 A091314 * A091316 A091317 A091318 KEYWORD nonn AUTHOR Thomas Ward (t.ward(AT)uea.ac.uk), Feb 24 2004 EXTENSIONS Name clarified by Michel Marcus, May 14 2015 STATUS approved

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Last modified August 18 15:00 EDT 2019. Contains 326106 sequences. (Running on oeis4.)