22695

Appears in sequences

• Number of esters with n carbon atoms up to structural isomerism.at n=12A000632
• Odd composite numbers k such that cototient(k) - phi(k) = k - 2*phi(k) is an odd prime.at n=9A083255
• Number of n X 5 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically.at n=8A207596
• G.f.: exp( Sum_{n>=1} x^n/n * Product_{k>=1} (1 + x^(n*k)*(1 + x^n)^k) ).at n=14A219229
• a(n) = floor(6^n/(2+2*cos(Pi/9))^n).at n=23A240733
• Number of partitions p of n such that the number of parts is a part or max(p) - min(p) is a part.at n=44A241386
• Number of nX6 0..1 arrays with every element equal to 1, 3, 5, 7 or 8 king-move adjacent elements, with upper left element zero.at n=19A298922
• a(n) = Sum_{k=1..n} k * tau(k)^2, where tau is A000005.at n=42A320896