20165

Appears in sequences

• Numbers k such that k, k+1, k+2 and k+3 have the same number of divisors.at n=26A006601
• McKay-Thompson series of class 8C for Monster.at n=8A052241
• a(n) = 4*prime(n)^2+1.at n=19A060429
• a(1)=3; a(2n), a(2n+1) are smallest integers > a(2n-1) such that a(2n-1)^2+a(2n)^2=a(2n+1)^2.at n=12A077034
• Numbers n for which there are exactly six k such that n = k + (product of nonzero digits of k).at n=13A096927
• Expansion of (chi(q)^5 * chi(-q))^2 in powers of q where chi() is a Ramanujan theta function.at n=16A143894
• 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), (0, 1, -1), (0, 1, 1), (1, 0, 0)}.at n=8A150164
• 5 times octagonal numbers: a(n) = 5*n*(3*n-2).at n=37A153795
• Hypotenuses of primitive Pythagorean triples in A195565 and A195566.at n=5A195567
• a(n) = 13*n^2 - 16*n + 5.at n=40A202141
• E.g.f. satisfies: A'(x) = (cos(x) + sin(x)*A(x)) / (cos(x)*A(x) - sin(x)).at n=10A245115
• Numbers k such that A248891(k) = 1.at n=11A248901
• Number of (n+3)X(1+3) 0..1 arrays with each row and column divisible by 13, read as a binary number with top and left being the most significant bits.at n=14A262482
• Fixed points of A275957; numbers n for which A060125(n) = A225901(n).at n=44A275843
• Record values of A018799 (Smallest nonnegative integer m such that m! begins with n in base 10).at n=27A279089
• Expansion of Product_{k>=1} ((1 - x^(7*(2*k-1))) * (1 - x^(7*k)) / (1 - x^k)).at n=41A280937
• Numbers of the form m^2 + 1 that can be expressed in more than one way as j^2 + k^2 with j > k > 1.at n=25A299708
• Numbers of the form m^2 + 1 that can be expressed in more than one way as j^2 + k^2 with j > k > 1 and gcd(j,k) = 1.at n=12A300166