OFFSET
1,2
COMMENTS
LINKS
Kevin Ryde, Table of n, a(n) for n = 1..8192
Martin Fürer, Faster integer multiplication, Proceedings of the 39th Annual ACM Symposium on Theory of Computing, 11-13 June 2007. And in SIAM Journal of Computing, volume 30, number 3, 2009, pages 979-1005.
FORMULA
a(n) = 2^A001069(n).
a(n) = 2^lg*(n), where lg*(x) = 0 if x <= 1 and 1 + lg*(log_2(x)) otherwise. - Charles R Greathouse IV, Apr 09 2012
PROG
(PARI) a(n)=my(t); while(n>1, n=log(n+.5)\log(2); t++); 2^t \\ Charles R Greathouse IV, Apr 09 2012
(PARI) a(n) = my(c=0); while(n>1, n=logint(n, 2); c++); 1<<c; \\ Kevin Ryde, May 18 2020
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Kevin Ryde, May 10 2020
STATUS
approved