Search: id:A006368 Results 1-1 of 1 results found. %I A006368 M2249 %S A006368 0,1,3,2,6,4,9,5,12,7,15,8,18,10,21,11,24,13,27,14,30,16,33,17,36,19,39, %T A006368 20,42,22,45,23,48,25,51,26,54,28,57,29,60,31,63,32,66,34,69,35,72,37, %U A006368 75,38,78,40,81,41,84,43,87,44,90,46,93,47,96,49,99,50,102,52,105,53 %N A006368 If n even then 3n/2 otherwise nearest integer to 3n/4. %C A006368 a(n)=-a(-n). %C A006368 a(n)=A006369(n)-A168223(n); A168221(n)=a(a(n)); A168222(a(n))=A006369(n). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 20 2009] %D A006368 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %D A006368 S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992. %D A006368 R. K. Guy, Unsolved Problems in Number Theory, E17. %H A006368 R. Zumkeller, Table of n, a(n) for n = 0..10000 [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 20 2009] %H A006368 Index entries for two-way infinite sequences %H A006368 S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992. %H A006368 S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992. %H A006368 Index entries for sequences that are permutations of the natural numbers %F A006368 G.f.: x(1+3x+x^2+3x^3+x^4)/((1-x^2)(1-x^4)). a(2n)=3n, a(4n+1)=3n+1, a(4n-1)=3n-1. - Michael Somos, Jul 23, 2002 %e A006368 9 is odd so a(9)=round(3*9/4)=round(7-1/4)=7. %p A006368 A006368:=(1+3*z+z**2+3*z**3+z**4)/(1+z**2)/(z-1)**2/(1+z)**2; [Conjectured by S. Plouffe in his 1992 dissertation.] %o A006368 (PARI) a(n)=(3*n+n%2)\(2+n%2*2) %o A006368 (PARI) a(n)=if(n%2,round(3*n/4),3*n/2) %Y A006368 Inverse mapping to A006369. %Y A006368 Cf. A028397. %Y A006368 Sequence in context: A064789 A093050 A054089 this_sequence A105354 A094077 A091018 %Y A006368 Adjacent sequences: A006365 A006366 A006367 this_sequence A006369 A006370 A006371 %K A006368 nonn,nice,easy,new %O A006368 0,3 %A A006368 N. J. A. Sloane (njas(AT)research.att.com) and J. H. Conway (conway(AT)math.princeton.edu) %E A006368 More terms from Jason Earls (zevi_35711(AT)yahoo.com), Jul 12 2001 %E A006368 Edited by Michael Somos, Jul 23, 2002 Search completed in 0.001 seconds