36576

Appears in sequences

• a(n) = n! * Sum_{j=0..floor(n/2)} (-1)^j/binomial(n,j).at n=8A024420
• Numbers m such that uphi(sigma(m)) = 2m, where the unitary phi function (A047994) is defined by: if x = p1^r1*p2^r2*p3^r3*... then uphi(x) = (p1^r1 - 1)*(p2^r2 - 1)*(p3^r3 - 1)*...at n=11A030165
• Numbers k such that nusigma(usigma(k)) = 2k, where usigma(k) is the sum of unitary divisors of k (A034448) and nusigma(k) is the sum of non-unitary divisors of k (A048146).at n=4A063891
• Numbers k such that the number of steps to reach 1 in '3x+1' problem equals tau(k), the number of divisors of k.at n=43A070980
• Maximal number of 15432 patterns in a permutation of 1,2,...,n.at n=26A100355
• a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4, with initial terms -1,3,2,1.at n=23A111572
• 10-gonal numbers for which the sum of the digits is also a 10-gonal number.at n=12A119547
• The number of bijections f:{1,...,n}->Z/nZ such that f(ab)=f(a)+f(b) whenever all three function values are defined.at n=25A179989
• Conjectured list of fully multisociable numbers.at n=34A183029
• Number of 3-step one or two space at a time rook's tours on an n X n board summed over all starting positions.at n=26A187288
• Numbers k such that both k and k^2 are sums of a twin prime pair.at n=11A213784
• Number of n X 3 arrays of the minimum value of corresponding elements and their horizontal, vertical, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..1 n X 3 array.at n=31A219349
• Number of (n+4)X7 0..2 matrices with each 5X5 subblock idempotent.at n=6A224620
• Number of (n+4) X 11 0..2 matrices with each 5 X 5 subblock idempotent.at n=2A224624
• 60-gonal (hexacontagonal) numbers: a(n) = n(29n - 28).at n=36A249911
• Number of (n+2)X(6+2) 0..1 arrays with every 3X3 subblock sum of the two medians of the central row and column plus the two sums of the diagonal and antidiagonal nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=15A259004
• Numbers k such that k*A001414(k)+1 is the square of a prime.at n=29A343141
• Number of polygons formed when every pair of vertices of a regular n-gon are joined by an infinite line.at n=24A344857
• Number of polygons formed when every pair of vertices of a regular (2n-1)-gon are joined by an infinite line.at n=12A344866
• Let S(n)=sigma(n)/3. Numbers k such that S^m(k)=k, 1/3-sociable numbers (of any order).at n=10A356548