OFFSET
0,2
COMMENTS
2^n <= A239697(n) <= a(n). - Michael S. Branicky, Oct 02 2020
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..50 (terms 0..30 from Michael S. Branicky and terms 31..35 from David A. Corneth)
Andrew Howroyd, PARI Program
EXAMPLE
a(4)=88 because 88 is the smallest palindromic number with 4 prime factors, 2^3*11 (counted with multiplicity).
PROG
(Python)
from sympy import factorint
def A076886(n):
d = 1
while True:
half = (d+1)//2
for left in range(10**(half-1), 10**half):
strleft = str(left)
if d%2 == 0:
m = int(strleft + strleft[::-1])
else:
m = int(strleft + (strleft[:-1])[::-1])
if sum(list(factorint(m).values())) == n:
return m
d += 1
print([A076886(n) for n in range(17)]) # Michael S. Branicky, Oct 02 2020
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Shyam Sunder Gupta, Nov 25 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Dec 02 2002
a(26) corrected and a(27)-a(28) from Michael S. Branicky, Oct 02 2020
STATUS
approved