20424

Appears in sequences

• tan(arcsinh(x)*log(x+1))=2/2!*x^2-3/3!*x^3+4/4!*x^4-20/5!*x^5...at n=8A012575
• arctanh(arcsinh(x)*log(x+1))=2/2!*x^2-3/3!*x^3+4/4!*x^4-20/5!*x^5...at n=8A012580
• Base-9 palindromes that start with 3.at n=29A043030
• a(n) = Sum_{h=0..n, k=0..n} T(h,k), array T counting knights' moves as in A049604.at n=37A047881
• Number of reversible strings with n beads using exactly four different colors.at n=7A056311
• McKay-Thompson series of class 36D for the Monster simple group.at n=46A058647
• a(n) = 3*(n - 2)*(5*n -11).at n=37A060785
• Product of prime(n+1)-1 and prime(n)-1.at n=33A083553
• (prime(n-1) + 1)*(prime(n+1) - 1).at n=32A087105
• a(n) = n*(n+5)*(50+45*n+n^2)/24.at n=17A101861
• Number of primes between (prime(n + 1))^Pi and (prime(n))^Pi.at n=28A137380
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (0, 0, 1), (0, 1, 0), (1, -1, 0), (1, 0, -1)}.at n=8A150153
• Expansion of q^(-1) * f(-q^3) * phi(-q^3) / (phi(-q^2) * psi(-q^9)) in powers of q where f(), phi(), psi() are Ramanujan theta functions.at n=46A186115
• Expansion of (phi(-q^3) / phi(-q))^2 in powers of q where phi is a Ramanujan theta function.at n=15A186924
• McKay-Thompson series of class 36D for the Monster group with a(0) = 2.at n=46A186964
• McKay-Thompson series of class 36D for the Monster group with a(0) = 1.at n=46A187020
• Number of -2..2 arrays x(0..n-1) of n elements with zeroth through n-1st differences all nonzero.at n=8A199937
• Principal diagonal of the convolution array A213747.at n=5A213748
• Expansion of (phi(-x) / phi(-x^3))^2 in powers of x where phi() is a Ramanujan theta function.at n=45A217771
• Expansion of chi(q) * chi(-q^9) / (chi(-q) * chi(q^9)) in powers of q where chi() is a Ramanujan theta function.at n=45A261156