24861

Appears in sequences

• Numbers n such that 9*10^n + 8*R_n - 7 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=12A103107
• Number of n X 2 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 3 binary array having determinant equal to one, with rows and columns of the latter in nondecreasing lexicographic order.at n=27A227637
• The Wiener index of the graph obtained by applying Mycielski's construction to a benzenoid consisting of a linear chain of n hexagons.at n=15A228597
• If n is composite, replace n with the concatenation of its nontrivial divisors, written in increasing order, each divisor being written in base 10 with its digits in reverse order, otherwise a(n) = n.at n=31A361320