[go: up one dir, main page]

login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

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
OFFSET
1,1
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..370 (terms 1..210 from Robert Israel)
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:
seq(A[n], n=1..100); # Robert Israel, Jul 15 2014
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
print(list(islice(agen(), 17))) # Michael S. Branicky, Jun 23 2022
CROSSREFS
KEYWORD
base,nonn
AUTHOR
G. L. Honaker, Jr., Jan 18 2000
EXTENSIONS
Definition corrected by Robert Israel, Jul 15 2014
STATUS
approved