20385

Appears in sequences

• Number of ordered multigraphs on n labeled edges (with loops).at n=5A020559
• Numbers n such that sopf(n) = sopf(n-1) + sopf(n-2), where sopf(x) = sum of the distinct prime factors of x.at n=10A075565
• Sums of groups in A075639.at n=18A075640
• Diagonal in array of n-gonal numbers A081422.at n=26A081437
• Number of pairs with two different elements which can be obtained by selecting unique elements from two sets with n+1 and n^2 elements respectively and n common elements.at n=27A085490
• Numbers n such that p = n^2 + 2, p+2 and p+6 are consecutive primes.at n=29A086380
• This table shows the coefficients of combinatorial formulas needed for generating the sequential sums of p-th powers of binomial coefficients C(n,6). The p-th row (p>=1) contains a(i,p) for i=1 to 6*p-5, where a(i,p) satisfies Sum_{i=1..n} C(i+5,6)^p = 7 * C(n+6,7) * Sum_{i=1..6*p-5} a(i,p) * C(n-1,i-1)/(i+6).at n=12A087110
• Triangle read by rows: T(0,0)=1; for n >= 1 T(n,k) is the coefficient of x^k in the monic characteristic polynomial of the tridiagonal n X n matrix with main diagonal 5,5,5,... and sub- and superdiagonals 1,1,1,... (0 <= k <= n).at n=31A123967
• 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, -1, 0), (-1, 0, 0), (1, -1, 0), (1, 0, 1), (1, 1, -1)}.at n=9A148960
• a(n) = 26*n^2 + 1.at n=28A158549
• Triangle of coefficients of Chebyshev's S(n,x+5) polynomials (exponents of x in increasing order).at n=31A207824
• Deficient numbers n having a companion m > n such that sigma(n)/n = sigma(m)/m.at n=36A212608
• Li estimate of the number of primes in successive power of two intervals [2^i, 2^(i+1)) for i >= 1.at n=17A223900
• 60-gonal (hexacontagonal) numbers: a(n) = n(29n - 28).at n=27A249911
• Irregular triangle read by rows. Row n gives the coefficients of the polynomial multiplying the exponential function in the e.g.f. of the (n+1)-th diagonal sequences of triangle A008459 (Pascal squares). T(n,k) for n >= 0 and k = 0..2*n.at n=40A290310
• Let q be the n-th prime power (A246655), then a(n) = q^3 + q^2 - q; number of solutions to x*y = z*w in the finite field F_q.at n=14A367014
• Expansion of (1 - x^3 - x^4)/((1 - x^3 - x^4)^2 - 4*x^7).at n=30A376730