19904

Appears in sequences

• Numbers k such that 87*2^k+1 is prime.at n=30A032393
• Number of (n+2)X(n+2) binary arrays with 3X3 subblock sums nondecreasing rightwards and downwards.at n=1A186831
• Number of (n+2)X4 binary arrays with 3X3 subblock sums nondecreasing rightwards and downwards.at n=1A186833
• T(n,k)=Number of (n+2)X(k+2) binary arrays with 3X3 subblock sums nondecreasing rightwards and downwards.at n=4A186840
• T(n,k)=Equals one maps: number of nXk binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal and antidiagonal neighbors in a random 0..1 nXk array.at n=37A220579
• Equals one maps: number of 2Xn binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal and antidiagonal neighbors in a random 0..1 2Xn array.at n=7A220580
• Record-breaking values, for increasing positive integers k == 1 or 5 mod 6, of the conjectured length of the longest primitive cycle(s) of positive integers under iteration by the Collatz-like 3x+k function.at n=31A226670
• Number of (2+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 1 3 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 1 3 6 or 7.at n=8A252307
• Expansion of (phi(-x^2) * phi(-x^4)^2 / phi(-x)^3)^2 in powers of x where phi() is a Ramanujan theta function.at n=6A258591
• Expansion of (phi(q^4) / phi(q))^2 in powers of q where phi() is a Ramanujan theta function.at n=12A260186
• Numbers k such that the decimal number concat(4,k) is a square.at n=37A273359
• Number of nX3 0..1 arrays with every element equal to 0, 2, 3, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=7A303079
• T(n,k)=Number of nXk 0..1 arrays with every element equal to 0, 2, 3, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=52A303084
• Number of length-n binary words containing no instance of the pattern x y y x^R where x and y are nonempty.at n=49A305694
• E.g.f. satisfies A(x) = -log(1 - x * exp(A(x))) * exp(A(x)).at n=5A357343