20907

Appears in sequences

• Concatenations C1 and C2 and C3 are all prime (see the comment lines).at n=4A034818
• Numbers whose base-12 representation has exactly 5 runs.at n=13A043654
• Number of 4 X n binary matrices such that any 2 rows have a common 1, up to column permutations.at n=6A052388
• Triangle T(n, k) = coefficients of ( t(n, x) ) where t(n, x) = (1-x)^(n+1)*p(n, x)/x, p(n, x) = x*D( p(n-1, x) ), with p(1, x) = x/(1-x)^2, p(2, x) = x*(1+x)/(1-x)^3, and p(3, x) = x*(1+6*x+x^2)/(1-x)^4, read by rows.at n=31A166344
• Triangle T(n, k) = coefficients of ( t(n, x) ) where t(n, x) = (1-x)^(n+1)*p(n, x)/x, p(n, x) = x*D( p(n-1, x) ), with p(1, x) = x/(1-x)^2, p(2, x) = x*(1+x)/(1-x)^3, and p(3, x) = x*(1+6*x+x^2)/(1-x)^4, read by rows.at n=32A166344
• Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^4>x^4+y^4.at n=41A211653
• Number of n X 2 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 3 binary array having a sum of zero, with rows and columns of the latter in lexicographically nondecreasing order.at n=26A227121
• Number of nX5 0..1 arrays with every element equal to 1, 3, 5, 7 or 8 king-move adjacent elements, with upper left element zero.at n=21A298921