The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A014222 a(0) = 0; thereafter a(n+1) = 3^a(n). 10
 0, 1, 3, 27, 7625597484987 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Alternative definition: a(n+1) = H_4(3,n) the tetration (repeated exponentiation) of 3 times n. For definition of and references concerning H_n(x,y) see A054871. Next term is 12580...39387 and has 3638334640025 digits [From Shawn Ligocki (sligocki(AT)gmail.com), Oct 08 2009] LINKS FORMULA a(n+1) = H_4(3,n) = 3^^n; a(0) = 0, a(1) = 1, a(n+1) = 3^3^...^3 (n times). EXAMPLE a(0) = H_4(3,-1)= 0; a(1) = H_4(3,0) = 1; a(2) = H_4(3,1) = 3; a(3) = H_4(3,2) = 3^3 = 27; a(4) = H_4(3,3) = 3^3^3 = 7625597484987; a(5) = H_4(3,4) = 3^3^3^3 = 3^7625597484987 > 10^3638334640025. MATHEMATICA NestList[3^#&, 0, 4] (* Harvey P. Dale, Apr 04 2013 *) CROSSREFS Cf. A014221 (a(n+1) = 2^a(n), or H_4(2,n)), A081651, A114561, A266199 (H_5(3,n)). Sequence in context: A068222 A308384 A055777 * A071107 A162414 A188927 Adjacent sequences:  A014219 A014220 A014221 * A014223 A014224 A014225 KEYWORD nonn,easy AUTHOR EXTENSIONS Revised using hyperoperation notation by Natan Arie Consigli, Jan 16 2016 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 30 13:46 EDT 2020. Contains 337439 sequences. (Running on oeis4.)