19871

Appears in sequences

• Octahedral numbers: a(n) = n*(2*n^2 + 1)/3.at n=31A005900
• a(n) = (2*n - 1)*(8*n^2 - 8*n + 3)/3.at n=15A063496
• First of three consecutive Ulam numbers (A002858) in arithmetic progression with difference 22.at n=11A068856
• Indices of record values in A228098.at n=9A230777
• Number of partitions p = [x(1), ..., x(k)], where x(1) >= x(2) >= ... >= x(k), of n such that max(x(i) - x(i-1)) > number of parts of p.at n=47A241832
• Semiprimes of the form (2*n^3+n)/3.at n=9A245232
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 201", based on the 5-celled von Neumann neighborhood.at n=18A279807
• a(n) is the least k such that there are exactly n primes between prime(k) + 1 and floor(prime(k + 1)^2/prime(k)) (inclusive) or 0 if no such k exists.at n=9A344582
• Partial sums of the odd triangular numbers (A014493).at n=30A352116