118440

Appears in sequences

• Vampire numbers (definition 2): numbers n with an even number of digits which have a factorization n = i*j where i and j have the same number of digits and the multiset of the digits of n coincides with the multiset of the digits of i and j.at n=17A014575
• Number of segments (and sides) created by diagonals of an n-gon in general position.at n=33A014628
• a(n) = (2^(n-1)/(2n)!)*Product_{k=1..n} q(k) where q(n) is the denominator of B(2n), the 2n-th Bernoulli number.at n=22A069267
• Product of Fibonacci and (shifted) triangular numbers.at n=16A086926
• Row sums of triangle A134392.at n=34A134393
• Subset of A020342 (vampire numbers, definition 1) listing numbers which have more than one such representation of the desired form.at n=26A144563
• First differences of harmonic (or Ore) numbers A001599.at n=32A153789
• Molecular topological indices of the sun graphs.at n=29A192845
• (n-1)-st elementary symmetric function of the first n terms of the lower Wythoff sequence, A000201.at n=6A203236
• a(n) is the least positive number whose divisors have all possible residues mod n.at n=46A280171
• The smallest number whose divisor set mod p has p elements with p = prime(n).at n=14A378272
• E.g.f. A(x) satisfies A(x) = exp( x^3 * A(x) / (1-x) ) / (1-x).at n=7A389869