|
|
A053583
|
|
a(n+1) is the smallest prime ending with (but not equal to) a(n), where a(1)=3.
|
|
10
|
|
|
3, 13, 113, 2113, 12113, 612113, 11612113, 1611612113, 111611612113, 1111611612113, 81111611612113, 2181111611612113, 132181111611612113, 11132181111611612113, 3411132181111611612113, 413411132181111611612113, 12413411132181111611612113
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
MAPLE
|
A[1]:= 3;
for n from 2 to 100 do
d:= 10^(ilog10(A[n-1])+1);
for k from 1 do
p:= A[n-1]+d*k;
if isprime(p) then
A[n]:= p;
break
fi
od
od:
|
|
PROG
|
(Python)
from sympy import isprime
from itertools import count, islice
def agen(an=3):
while True:
yield an
pow10 = 10**len(str(an))
for t in count(pow10+an, step=pow10):
if isprime(t):
an = t
break
|
|
CROSSREFS
|
|
|
KEYWORD
|
base,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|