19240

Appears in sequences

• McKay-Thompson series of class 10A for Monster.at n=11A058097
• Integers k such that phi(prime(k)+1) = phi(prime(k)-1).at n=12A066902
• a(1) = a(2) = 1; for n>2, a(n+1) = a(n) + a(n-1) iff n is prime, otherwise a(n+1) = a(n) + 1.at n=44A113050
• a(n) = 144*n^2 - 127*n + 28.at n=11A156719
• Expansion of (1 + x + x^2)/(1 - x^2 - 2*x^3).at n=24A159288
• Primitive triangle numbers as defined in A218243.at n=35A218392
• Number of orbits of Aut(Z^7) as function of the infinity norm n of the representative lattice point of the orbit, when the cardinality of the orbit is equal to 13440.at n=40A266398
• a(n) = n*((4*n + 1)*(7*n - 4) + 15*n*(-1)^n)/48.at n=31A302766
• Numbers k such that A011772(k) > A344878(k) and A011772(k) is a divisor of A344875(k).at n=15A344595
• Numbers whose square can be represented in exactly two ways as the sum of a positive square and a positive fourth power.at n=41A345700
• 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=42A358465
• Table read by antidiagonals: Place k equally spaced points on each side of a regular n-gon and join every pair of these n*k points by a chord; T(n,k) (n >= 3, k >= 0) gives the number of edges in the resulting planar graph.at n=41A367305
• Irregular triangle read by rows: T(n,k) = (2^floor(n/2)+k)-th numerator coefficient of the polynomial q_n used to parametrize the canonical stribolic iterates h_n (of order 1), for n=0,1,2,... and 0 <= k <= A000045(n+1) - 2^floor(n/2).at n=15A369992
• Numbers k which have a factorization k = f1*f2*...*fr where the digits of {k, f1, f2, ..., fr} together give 0,1,...,9 exactly once.at n=18A370970
• Composite numbers with properties that its digits (which may appear with multiplicity) may not appear in any of its factors (wherein the digits may also appear with multiplicity) and the combined digits of the product and the factors must have at least one of each of the ten digits.at n=34A370972
• Numbers k which have a factorization k = f_1*f_2*...*f_r where f_i >= 1 and the digits of {k, f_1, f_2, ..., f_r} together give 0,1,...,9 exactly once.at n=34A372259