20566

Appears in sequences

• Number of simple perfect squared squares of order n up to symmetry.at n=29A006983
• a(n) = (2*n + 1)*(5*n + 1).at n=45A033571
• Number of EE's crossing the line y = x (i.e., two consecutive E steps from the line y = x+1 to the line y = x-1) in all Delannoy paths of length n.at n=7A110127
• Expansion of x^9/((1-x)*(1-x^2)*(1-x^3))^2.at n=33A117485
• Heptagonal numbers for which the digital root is also a heptagonal number.at n=41A117663
• Heptagonal numbers divisible by 7.at n=26A117795
• Heptagonal numbers A000566 which are the sum of two other heptagonal numbers > 0.at n=9A133251
• a(n) = 686*n - 14.at n=29A157363
• A triangular array distributing the values of sequence A120380.at n=18A160645
• Expansion of (1+13*x+32*x^2+13*x^3+x^4)/(1-x)^5.at n=9A160765
• Number of nondecreasing arrangements of 4 numbers in -(n+2)..(n+2) with sum zero and not more than two numbers equal.at n=41A188237
• Expansion of Product_{k>=0} (1 + x^(5*k+4))^(5*k+4).at n=52A285340
• Heptagonal numbers which are products of four distinct primes.at n=4A351867
• a(n) is the number of 2 X 2 matrices with elements 1..n where at least one row and at least one column is strictly increasing.at n=14A390922