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A093889 a(n) = n!/A093888(n). 1
1, 1, 1, 1, 3, 15, 80, 20, 160, 1440, 75, 825, 9900, 128700, 165888, 2488320, 39813120, 597196800, 10749542400, 125411328000, 2508226560000, 52672757760000, 2769091920000, 4901791334400, 117642992025600, 2941074800640000, 76467944816640000, 2064634510049280000, 57809766281379840000, 1676483222160015360000 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,5
LINKS
EXAMPLE
a(4) = 3 as the largest palindromic divisor of 4! comes from the set {1, 2, 3, 4, 6, 8, 12, 24}. The largest palindrome is this set is 8 so a(4) = 4! / 8 = 3. - David A. Corneth, Oct 12 2022
PROG
(Python)
from sympy import divisors, factorial, multiplicity
def ispal(n): s = str(n); return s == s[::-1]
def b(f, k): return f//k**multiplicity(k, f)
def a(n):
f = factorial(n)
m2 = max(d for d in divisors(b(f, 2), generator=True) if ispal(d))
m5 = max(d for d in divisors(b(f, 5), generator=True) if ispal(d))
return f//max(m2, m5)
print([a(n) for n in range(34)]) # Michael S. Branicky, Oct 12 2022
CROSSREFS
Sequence in context: A137957 A002514 A319216 * A369085 A020044 A024338
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Apr 23 2004
EXTENSIONS
Corrected and extended by Jason Earls, May 07 2004
a(0) and more terms from David A. Corneth, Oct 07 2022
STATUS
approved

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Last modified March 28 14:38 EDT 2024. Contains 371254 sequences. (Running on oeis4.)