|
|
A175733
|
|
a(n) is the smallest n-digit number with 3 divisors.
|
|
6
|
|
|
4, 25, 121, 1369, 10201, 100489, 1018081, 10004569, 100140049, 1000267129, 10000600009, 100008370081, 1000006000009, 10000033772089, 100000380000361, 1000000025191729, 10000001400000049, 100000000621806289, 1000000014000000049, 10000000055856073561
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
|
|
MATHEMATICA
|
Table[Prime[1 + PrimePi[Sqrt[10^n]]]^2, {n, 0, 25}] (* T. D. Noe, Aug 19 2011 *)
|
|
PROG
|
(Python)
from math import sqrt
from sympy import nextprime
def a(n): return nextprime(int(sqrt(10**n+1)))**2
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|