OFFSET
0,1
LINKS
Iain Fox, Table of n, a(n) for n = 0..10000
FORMULA
For n > 0, a(n) = ceiling((d + n/10^d)^8) where d = 1 + floor(log_10(n)). - Jon E. Schoenfield, Dec 09 2017
EXAMPLE
a(20) = 549 -> 549^(1/8) = 2.{20}012088...;
a(21) = 570 -> 570^(1/8) = 2.{21}046863... and a(20)=549 < a(21)=570.
From Jon E. Schoenfield, Dec 09 2017: (Start)
n a(n) a(n)^(1/8)
-- ---- ---------------
0 2 1.{0}9050773...
1 3 1.{1}4720269...
2 5 1.{2}2284454...
3 9 1.{3}1607401...
4 15 1.{4}0285055...
5 26 1.{5}0269786...
6 43 1.{6}0023423...
7 70 1.{7}0073737...
8 111 1.{8}0162903...
9 170 1.{9}0022975...
10 379 2.{10}053489...
11 393 2.{11}008071...
12 409 2.{12}063250...
...
99 6389 2.{99}005454...
100 8529 3.{100}00407...
101 8551 3.{101}00247... (End)
PROG
(PARI) a(n) = if(n == 0, return(2)); my(d = 1 + logint(n, 10)); ceil((d + n/10^d)^8); \\ Iain Fox, Dec 09 2017
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Sep 15 1998
EXTENSIONS
Name edited by Jon E. Schoenfield, Dec 09 2017
STATUS
approved