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 A028397 Start at n and iterate the map in A006368; a(n) is the smallest number in the trajectory. 6
 0, 1, 2, 2, 4, 4, 4, 4, 8, 4, 8, 8, 12, 8, 14, 8, 16, 8, 18, 14, 20, 16, 14, 8, 24, 14, 14, 20, 14, 14, 30, 8, 32, 14, 32, 14, 36, 14, 32, 14, 40, 8, 14, 32, 44, 32, 46, 14, 48, 14, 50, 32, 50, 40, 46, 8, 56, 32, 14, 44, 60, 46, 44, 14, 64, 14, 44, 50, 8, 50, 44, 40, 72, 8, 44, 56 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS T. D. Noe, Table of n, a(n) for n = 0..1000 EXAMPLE Sample iteration: 7->5->4->6->9->7 so a(7)=4. Sample iteration: 12->18->27->20->30->45->34->51->... so a(12)=12. MATHEMATICA Table[Min[NestList[If[EvenQ[#], (3#)/2, Floor[(3#+2)/4]]&, n, 100]], {n, 0, 80}] (* Harvey P. Dale, May 02 2012 *) PROG (Perl) \$|=1; for(\$n=1;; ++\$n){ \$m=\$n; \$d{\$m}=\$n, \$m=f(\$m) while !\$d{\$m}; (Perl) if (\$m<\$n){ (\$c, \$m)=(\$d{\$m}, \$n); \$d{\$m}=\$c, \$m=f(\$m) while \$m >= \$n } (Perl) print"\$d{\$n}, " } sub f { \$_[0]%2 ? int((3*\$_[0]+1)/4) : 3*\$_[0]/2 } (PARI) a(n)=local(m); if(n<=0, 0, m=n; while((m!=n=(3*n+n%2)\(2+n%2*2))&n<10^99, m=min(m, n)); m) CROSSREFS Cf. A006368, A180853, A028393, A028395. Sequence in context: A279506 A105678 A309195 * A053644 A279170 A292254 Adjacent sequences:  A028394 A028395 A028396 * A028398 A028399 A028400 KEYWORD nonn,nice AUTHOR EXTENSIONS More terms from Hugo van der Sanden STATUS approved

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Last modified February 24 10:27 EST 2020. Contains 332209 sequences. (Running on oeis4.)