Search: id:A006961 Results 1-1 of 1 results found. %I A006961 M2584 %S A006961 1,1,3,6,15,31,75,164,388,887,2092,4884,11599,27443,65509,156427,375263 %N A006961 Mappings from n points to themselves with in-degree <= 2. %D A006961 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %D A006961 N. G. de Bruijn and D. A. Klarner, Multisets of aperiodic cycles, SIAM J, Algeb. Discrete Meth., 3 (1982), 359-368. %Y A006961 Cf. A006961. %Y A006961 Sequence in context: A034739 A097941 A117161 this_sequence A034740 A152167 A105476 %Y A006961 Adjacent sequences: A006958 A006959 A006960 this_sequence A006962 A006963 A006964 %K A006961 nonn,easy,nice %O A006961 0,3 %A A006961 Simon Plouffe (simon.plouffe(AT)gmail.com) Search completed in 0.001 seconds