28985

Appears in sequences

• Convolution of the lower and upper Wythoff sequences (A000201 and A001950).at n=33A023664
• Numbers that are sums of 2 or more consecutive squares in more than 1 way.at n=36A062681
• Numbers n such that the middle coefficient of the cyclotomic polynomial Phi_n(x) has a value not obtained for any smaller n.at n=17A095877
• Expansion of sec(arctanh(x)).at n=4A102075
• a(n) is the number m such that f(sqrt(n)) is in the field Q(sqrt(m)), where f(x) is defined from the continued fraction x = [c(0), c(1), ... ] as [1/c(0), 1/c(1), ...].at n=43A229956
• a(n) is the number m such that f(sqrt(n)) is in the field Q(sqrt(m)), where f(x) is defined from the continued fraction x = [c(0),c(1),...] as [c(0)+2, c(1)+2,...].at n=27A229958
• Squarefree numbers which yield zero when their prime factors are xored together.at n=16A235488
• 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 26880.at n=34A266397
• Numbers that can be written as the sum of four or more consecutive squares in more than one way.at n=27A307937
• a(n) = (1/24)*n*(n - 1)*(n - 3)*(n - 14).at n=34A319930
• Place two n-gons with radii 1 and 2 concentrically, forming an annular area between them. Connect all the vertices with line segments that lie entirely within that area. Then a(n) is the number of regions in that figure.at n=28A337700
• Irregular triangle read by rows: T(n, k) is the q-multinomial coefficient defined by the k-th partition of n in Abramowitz-Stegun order, evaluated at q = 4.at n=14A347487
• Terms of A349937 that are not divisible by 3: numbers k > 1 not divisible by 2 or 3 such that A309906(k-1) < A309906(k) > A309906(k+1).at n=14A349941
• a(n) = J(n) * J(n+2) where J(n) = Jacobsthal(n) = A001045(n).at n=8A378676
• Integers in Ulam's spiral for which the numbers around them form a square whose four corners are all prime numbers.at n=19A383596
• Numbers m such that Stern polynomial B(m,x) has no irreducible polynomial factors that themselves are Stern polynomials. The initial a(1) = 1 is included by convention.at n=38A389918