20769

Appears in sequences

• Number of n-dimensional partitions of 5.at n=22A008779
• Numerators of continued fraction convergents to sqrt(739).at n=7A042422
• Number of labeled n-vertex graphs with a 2-component.at n=7A093351
• Numbers k such that k and 2*k, taken together are pandigital.at n=13A115922
• Numbers k such that k and 5*k, taken together, are pandigital.at n=13A115925
• Consider the tiling of the plane with squares of two different sizes as in Fig. 2.4.2(g) of Grünbaum and Shephard, p. 74. a(n) is the number of connected figures that can be formed on this tiling, from n tiles, each composed of a big square and an adjacent little square.at n=4A121196
• Numbers k such that k and k+1 have 4 distinct prime factors.at n=30A140078
• INVERT transform of A002321, Mertens's function.at n=24A144031
• Numbers n such that n+(n+1), n^2+(n+1)^2, n+(n+1)^2, n^2+(n+1) are all prime.at n=27A216270
• Denominators of rationals with e.g.f. D(4,x), a Debye function.at n=42A227574
• Numbers k such that k and k+1 are the product of exactly four distinct primes.at n=14A318896
• a(n) = Product_{1<=x<=n, n|(x^2-1)} x.at n=43A318909
• Numbers k such that k and k+1 each have at least 4 distinct prime factors.at n=30A321504
• Number of compositions of n with equal differences up to sign.at n=46A325557
• Odd composite integers m such that A014448(m) == 4 (mod m).at n=36A335670
• Odd composite integers m such that U(m)^2 == 1 (mod m) and V(m) == 4 (mod m), where U(m) and V(m) are the m-th generalized Lucas and Pell-Lucas numbers of parameters a=4 and b=-1, respectively.at n=29A337627
• Odd composite integers m such that A000032(3*m-J(m,5)) == 3*J(m,5) (mod m), where J(m,5) is the Jacobi symbol.at n=25A339724
• Odd composite integers m such that A000045(3*m-J(m,5)) == 1 (mod m), where J(m,5) is the Jacobi symbol.at n=29A340235
• Numbers which are the product of two S-primes (A057948) in exactly three ways.at n=17A343828
• Numbers k such that the k-th composition in standard order is an alternating permutation of {1..k} for some k.at n=40A349051