20153

Appears in sequences

• Record-setting differences between adjacent elements of the Mian-Chowla sequence variant A058335.at n=43A080931
• Expansion of x/((1-x-x^3)*(1-x)^6).at n=12A144900
• a(n) = 14*n^3 - 30*n^2 + 24*n - 7.at n=11A155883
• Integers of alternate form x+(x+1)^2+(x+2)^3+(x+3)^4+(x+4)^5+(x+5)^6.at n=5A179465
• Number of inequivalent (mod D_3) ways to place 3 points on a triangular grid of side n so that they are not vertices of an equilateral triangle of any orientation.at n=11A243142
• Semiprimes sp such that sp plus its digit sum is a perfect square.at n=22A244733
• a(n) is the smallest positive integer not yet in the increasing sequence that is obtained when the largest digit from a(n-1) is deleted and the remaining digits are permuted such that no digit in a(n) has the same position it had in a(n-1) (counting from left to right). No repeated digits allowed; a(1)=10.at n=18A302095
• G.f. A(x) satisfies: A(x) = 1 + x^2*A(x)^2/(1 - x*A(x) - x^2*A(x)^2 - x^3*A(x)^3).at n=12A307528
• Number of integer partitions of n such that the dual of the multiset partition obtained by factoring each part into prime numbers is a (strict) antichain, also called T_1 integer partitions.at n=39A326977
• Least area (doubled) of a triangle enclosing a circle of radius n such that the center of the circle and the vertices of the triangle all have integer coordinates.at n=43A358465
• Nonnegative integers k such that k! mod nextprime(k) is larger than k.at n=16A360805
• G.f. A(x) = exp( Sum_{n>=1} sigma(n)*sigma(2*n)/3 * x^n/n ), where sigma(n) = A000203(n) is the sum of the divisors of n.at n=14A382124