2018957

Properties

Appears in sequences

• a(n) = floor(Sum_{k=0..n} k!/2), or floor( A003422(n+1)/2 ).at n=10A014288
• a(n) is the smallest number m such that m! is divisible by the left factorial !n (A003422).at n=10A062549
• Triangle, read by rows, defined by: T(n,k) = (k+1)*T(n,k+1) - Sum_{j=1..n-k-1} T(j,0)*T(n,j+k+1) for n>k with T(n,n)=1 for n>=0.at n=56A117396
• Primes of the form !(k + 1)/2 = Sum_{i=0..k} i!/2.at n=6A124374
• Triangle read by rows: coefficients of the polynomial (Sum_{i=0..k} (Product_{j=0..i} (x+j)))/(x*(x+2)).at n=45A270250
• Numerator of probability that a permutation of elements of some subset of set {1,2,...,n} is a permutation of elements of some set of the form 1..k, k <= n.at n=9A293458
• Prime numbersat n=150255