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!)
 A244059 Initial digit of the decimal expansion of n^(n^(n^n)) or n^^4 (in Don Knuth's up-arrow notation). 1
 1, 1, 6, 1, 2, 1, 4, 7, 6, 2, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS This sequence can also be written as (nāā4) in Knuth up-arrow notation. 0^^4 = 1 since 0^^k = 1 for even k, 0 for odd k, k >= 0. Conjecture: the distribution of the initial digits obey G. K. Zipf's law. LINKS Cut the Knot.org, Benford's Law and Zipf's Law, A. Bogomolny, Zipf's Law, Benford's Law from Interactive Mathematics Miscellany and Puzzles. M. E. J. Newman, Power laws, Pareto distributions and Zipf's law. Eric Weisstein's World of Mathematics, Joyce Sequence Wikipedia, Knuth's up-arrow notation Wikipedia, Zipf's law EXAMPLE a(4)=2 because A241293(1)=2. PROG (PARI) a(n)=digits(n^n^n^n)[1] \\ impractical for large n; Charles R Greathouse IV, May 13 2015 CROSSREFS Cf. A241291, A241292, A241293, A241294, A241295, A241296, A241297, A243913, A241299. Sequence in context: A085552 A002950 A324046 * A121090 A321991 A010135 Adjacent sequences:  A244056 A244057 A244058 * A244060 A244061 A244062 KEYWORD nonn,hard,more,base AUTHOR Robert Munafo and Robert G. Wilson v, Jun 18 2014 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 January 25 01:49 EST 2020. Contains 331229 sequences. (Running on oeis4.)