19701

Appears in sequences

• Expansion of 1/((1-x)*(1-2*x)*(1-3*x)*(1-10*x)).at n=4A021049
• a(n) = T(n,1) + T(n-1,2) + ...+ T(n-k+1,k), where k = floor((n+1)/2) and T is the array defined in A026098.at n=45A026103
• a(n) = (n^2-1)*(2*n^2-1).at n=10A033595
• Triangular numbers whose index is a multiple of the sum of their digits.at n=35A067520
• a(n) = (25*n^2 - 15*n + 2)/2.at n=40A080857
• a(n) = p(n)*(p(n)-1)/2 where p(n) = upper member of n-th pair of twin primes.at n=14A082669
• Number of different initial values for 3x+1 trajectories started with initial values not exceeding 2^n and in which the peak values are larger than 2^n.at n=14A095383
• Indices of primes in sequence defined by A(0) = 61, A(n) = 10*A(n-1) + 21 for n > 0.at n=25A101525
• Triangular numbers equal to the difference between a prime number and its index.at n=32A115887
• Triangular numbers for which the sum of the digits is a heptagonal number.at n=23A117312
• Partial sums of n^(n^2), A002489.at n=3A120929
• a(n) = 3*n*(6*n + 1).at n=33A144314
• Partial sums of A000141.at n=15A175361
• a(n) = m*(m+1)/2, where m = floor(n^(3/2)).at n=33A185541
• Triangular numbers T from A000217 such that (4*T+1)/5 is prime.at n=38A207339
• Triangular numbers of the form 2p-1 where p is prime.at n=25A217000
• Number of compositions of n in which the maximal multiplicity of parts equals 3.at n=15A243120
• Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.at n=5A253449
• Number of (n+1) X (6+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.at n=0A253454
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.at n=15A253456