OFFSET
1,2
COMMENTS
LINKS
M. Fleuren, Factoring of the Smarandache Mirror Sequence.
F. Smarandache, Only Problems, Not Solutions!, Mirror sequence, problem 19, page 20.
EXAMPLE
a(4) = 2 since 4321234 = 2 * 2160617;
a(6) = 3 since 65432123456 = 2^6 * 7 * 146053847.
PROG
(Python)
from sympy import primefactors
def A361624(n): return len(primefactors(int(''.join(map(str, range(n, 1, -1)))+''.join(map(str, range(1, n+1)))))) # Chai Wah Wu, Mar 21 2023
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Bernard Schott, Mar 18 2023
EXTENSIONS
a(36)-a(54) from Amiram Eldar, Mar 19 2023
a(42) corrected by Sean A. Irvine, Sep 26 2023
a(55) from Sean A. Irvine, Oct 16 2023
STATUS
approved