21386

Appears in sequences

• s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Fibonacci numbers), t = (Lucas numbers).at n=15A025079
• 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=6A076527
• Greatest number m such that the fractional part of (11/10)^A153685(n) <= 1/m.at n=6A153689
• Greatest number m such that the fractional part of (11/10)^A153686(n) <= 1/m.at n=10A153690
• Number of nX5 1..4 arrays with all 1s connected, all 2s connected, all 3s connected, all 4s connected, 1 in the upper left corner, 2 in the upper right corner, 3 in the lower left corner, 4 in the lower right corner, and with no element having more than 2 neighbors with the same value.at n=8A164757
• Number of nondecreasing sequences of n 1..7 integers with every element dividing the sequence sum.at n=32A212535
• Indices of primes in A141523.at n=38A235862
• Numbers k such that 2*10^k - 43 is prime.at n=19A289753
• Number of nX3 0..1 arrays with every element equal to 2, 3, 4, 5, 6 or 7 king-move adjacent elements, with upper left element zero.at n=7A299329
• T(n,k) = Number of n X k 0..1 arrays with every element equal to 2, 3, 4, 5, 6 or 7 king-move adjacent elements, with upper left element zero.at n=47A299334
• T(n,k) = Number of n X k 0..1 arrays with every element equal to 2, 3, 4, 5, 6 or 7 king-move adjacent elements, with upper left element zero.at n=52A299334