43659

Appears in sequences

• Successive denominators of Wallis's approximation to Pi/2 (reduced).at n=10A001902
• Numerators of Hurwitz numbers H_n (coefficients in expansion of Weierstrass P-function).at n=3A002306
• Number of walks on square lattice.at n=17A005565
• From denominators in expansion of tan(arcsinh(x)) - sin(arctanh(x)).at n=7A068557
• Let W(n) = Product_{k=1..n} (1 - 1/(4*k^2)), the partial Wallis product (lim_{n->oo} W(n) = 2/Pi); then a(n) = numerator(W(n)).at n=5A069955
• Numbers n such that A001414(n) = sum of composites from the smallest prime factor of n to the largest prime factor of n.at n=21A074053
• Triangle read by rows: S_D(n,k) = `Type D' Stirling numbers of the second kind.at n=31A086364
• Numbers that have exactly seven prime factors counted with multiplicity (A046308) whose digit reversal is different and also has 7 prime factors (with multiplicity).at n=31A109027
• A symmetrical triangle of coefficients based on A001147: a(n)=(2*n-1)*a(n-1); t(n,m)=a(n)^2/((2*n - 1)*a(m)*a(n - m)).at n=24A143081
• a(n) = 361*n^2 - 2*n.at n=10A158307
• Least term of A094179 with exactly 2n divisors.at n=14A204046
• a(n) = ceiling( Pi^(n/3) ).at n=27A212463
• Smallest number having exactly n divisors ending with 3 or 7.at n=13A331082
• Number T(n,k) of endofunctions on [n] with exactly k isolated fixed points; triangle T(n,k), n >= 0, 0 <= k <= n, read by rows.at n=30A350212
• Odd numbers m such that there exists no k for which the denominator of d(k)/k = m where d(k) is the number of divisors of k (A000005).at n=34A353320
• Table T(r,s) read by rows: the coefficient of [k^s] of the Wynn's r-th converging polynomial p_r(k) of Weber functions, 0<=s<=r.at n=61A380169
• a(n) = denominator(r(n)) where r(n) = (n/2)*(Pi/2)^cos(Pi*(n-1))*((n/2-1/2)!/(n/2)!)^2.at n=11A380950
• Irregular triangle T(n,k), n >= 0, 0 <= k < 2^(n-1), where T(n,k) = Product_{j=0..n-1} prime(j+1)^((n-j)*d_j), where d_j is the bit with digit weight 2^j in the binary expansion of 2^(n-1)+k.at n=26A384003
• G.f. A(x) satisfies: A(x)^2 = A( x^2 + 4*A(x)^3 ).at n=6A386666