19580

Appears in sequences

• a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| <= 1 for i = 1,2,...,n, s(0) = 2, s(n) = 4. Also a(n) = T(n,n-2), where T is the array in A026323.at n=9A026327
• Number of ways to place a non-attacking white and black king on n X n chessboard.at n=11A035286
• a(n) = sigma_3(n) - sigma_2(n) - sigma_1(n).at n=26A092350
• Triangle read by rows giving the coefficients of general sum formulas of n-th Lucas numbers (A000204). The k-th row (k>=1) contains T(i,k) for i=1 to 2*k-1, where T(i,k) satisfies L(n) = Sum_{k=1..n} Sum_{i=1..2*k-1} T(i,k) * C(n-k,i-1) * n^(n-k) / (n-1)!.at n=18A101033
• Number of (ordered) sequences of coins (each of which has value 1, 5, 10, 25, 50 or 100) which add to n.at n=35A114044
• Successive sums of consecutive primes that form a triangular grid.at n=12A125130
• Numbers k such that k^2 divides 9^k - 1.at n=39A127101
• Numbers k such that k^2 divides 21^k-1.at n=35A128401
• Numbers k such that k^3 divides 3^(k^2) - 1.at n=39A129211
• a(n) = 49*n^2 - n.at n=19A157923
• a(n) = 196*n^2 - 2*n.at n=9A158224
• a(n) = 400*n^2 - 20.at n=6A158597
• Number of nX4 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,2,1,0,4 for x=0,1,2,3,4.at n=4A196978
• Number of nX5 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,2,1,0,4 for x=0,1,2,3,4.at n=3A196979
• T(n,k)=Number of nXk 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 3,2,1,0,4 for x=0,1,2,3,4.at n=31A196982
• T(n,k)=Number of nXk 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 3,2,1,0,4 for x=0,1,2,3,4.at n=32A196982
• Number of nXn 0..1 arrays with every element unequal to 0, 1, 2, 4, 5, 7 or 8 king-move adjacent elements, with upper left element zero.at n=4A317147
• Number of nX5 0..1 arrays with every element unequal to 0, 1, 2, 4, 5, 7 or 8 king-move adjacent elements, with upper left element zero.at n=4A317150
• T(n,k)=Number of nXk 0..1 arrays with every element unequal to 0, 1, 2, 4, 5, 7 or 8 king-move adjacent elements, with upper left element zero.at n=40A317153
• G.f.: Sum_{n>=0} (n+1)*(n+2)*(n+3)*(n+4)/4! * x^n * (1 + x^n)^n.at n=21A326005