19409

Appears in sequences

• Expansion of e.g.f. arctanh(sec(x) * log(x+1)).at n=7A012777
• Frobenius number of the numerical semigroup generated by three consecutive hexagonal numbers.at n=12A069758
• n(k) is the minimum number that require at least k to make Prime[n]+2*Prime[n+k] a prime.at n=50A114264
• a(n) = A030067(2^n + 2^(n-1) - 1) for n>=1, where A030067 gives the semi-Fibonacci numbers.at n=6A129094
• a(n) = (2*n^3 + 5*n^2 + 11*n)/2.at n=25A162263
• a(n) = A030068(4n+3).at n=47A169740
• Expansion of 1 / (1 - x - x^2 + x^3 - x^5 + x^15 - x^17 - x^18 + x^19 + x^20).at n=28A174650
• Least b > p_n^2 such that [p_1^2,p_2^2,...,p_n^2] in base b is prime, where p_j denotes the j-th prime.at n=32A224197
• Expansion of Product_{k>=1} (1 - x^(8*k))/(1 - x^k).at n=38A261775
• Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-1) + b(n-2), where a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4.at n=16A294414
• Number of edges in a polygon whose boundary consists of n+2 equally spaced points around a semicircle and n+2 equally spaced points along the diameter (a total of 2n+2 points). See Comments for precise definition.at n=12A334459