27487

Properties

Appears in sequences

• Pisot sequence T(7,10), a(n) = floor(a(n-1)^2/a(n-2)).at n=41A020752
• a(n) is the number of pairs of integer quadruples (b_1, b_2, b_3, b_4) and (c_1, c_2, c_3, c_4) satisfying 1 <= b_1 < b_2 < b_3 < b_4 < n, 1 <= c_1 < c_2 < c_3 < c_4 < n, b_i != c_j for all i,j = 1,2,3,4 and Product_{i=1..4} cos(2*Pi*b_i/n) = Product_{i=1..4} cos(2*Pi*c_i/n).at n=36A063780
• Numbers whose square root in base 10 starts with 10 distinct digits.at n=14A113507
• Triangle read by rows: T(n,k) = 2 * A011971(n,k) - 1.at n=42A136791
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, -1), (-1, 0, 0), (-1, 0, 1), (0, 1, 0), (1, -1, 0)}.at n=11A148283
• Numbers k such that Sum_{i=1..k} i^7 divides Product_{i=1..k} i^7.at n=30A166607
• a(n) is the smallest prime such that it and the previous four primes are all of the form x^2 + n * y^2.at n=21A212605
• Primes having only {2, 4, 7, 8} as digits.at n=40A386157
• Prime numbersat n=3004