27866

Appears in sequences

• Convolution of A000108 (Catalan numbers) with A020922.at n=4A045530
• Triangle related to A001700 and A000302 (powers of 4).at n=50A046658
• a(1) = 1; for n>1, a(n)= smallest number greater than the previous term such that a(n-1)*a(n) + 1 is a palindrome.at n=14A081941
• a(n) = K_4(n) = Sum_{k>=0} A090285(4,k)*2^k*binomial(n,k). a(n) = 2*(n^4+14*n^3+62*n^2+91*n+21)/3.at n=11A090296
• Numbers n for which number of iterations to reach the largest equals number of iterations to reach 1 from the largest in Collatz (3x+1) trajectory of n.at n=29A224303
• Number of (n+2) X (3+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010101 or 01010101.at n=9A259737
• Numbers k such that 34*10^k - 3 is prime.at n=24A280018
• Let f(n) = floor(r*floor(r*n)) = A341254(n), where r = (2 + sqrt(5))/2. Let a(1) = 1. Then a(n) = f(a(n-1)) for n >= 2.at n=7A341255