31020

Appears in sequences

• Expansion of 1/(1-x^4-x^5-x^6-x^7-x^8-x^9).at n=41A017831
• Numbers k whose decimal representation, read as a base-22 value and divided by k, yields an integer.at n=25A032575
• Number of partitions of n into parts not of the form 25k, 25k+7 or 25k-7. Also number of partitions with at most 6 parts of size 1 and differences between parts at distance 11 are greater than 1.at n=40A036006
• Row sums of triangle A091492.at n=50A091493
• Triangle read by rows: T(n,k) is number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1), U=(1,2), or d=(1,-1) and having abscissa of first return equal to 3k.at n=26A108439
• Numbers k such that k*(k+1)-1 and k*(k+1)+1 are twin primes and k*(k+3)-1 and k*(k+3)+1 are also twin primes.at n=19A138303
• a(n) = 1000*n + 20.at n=30A157510
• a(n) = 64*n^2 + 2*n.at n=22A158070
• Number of closed walks of length n in a kite graph (K4 with one edge deleted).at n=11A181626
• Coefficient of q^4 in the polynomial NT_{n,mu}(q).at n=7A235594
• Even numbers such that the sum of the even divisors and the sum of the odd divisors are a square or a cube.at n=23A263695
• "Inside numbers". Pick a term "t" and one of its digits "d". Now jump to the right over d digits if "d" is odd, and to the left over d digits if "d" is even. Whatever the "d" you choose, you will stay on "t".at n=31A284515
• Perimeters of more than one primitive 120-degree integer triangle.at n=23A350047