26856

Appears in sequences

• Numbers n such that 65*2^n-1 is prime.at n=27A050558
• Riordan array (1/sqrt(1-6x+5x^2),x/(1-6x+5x^2)).at n=39A111965
• Values of n such that (sigma(sigma(n))-phi(phi(n)))/n is an integer (the corresponding integral ratios are given in A136132).at n=25A136131
• Main diagonal of square arrays A114881 and A249741.at n=27A249743
• The total number of fires in a rooted undirected infinite 5-ary tree with a self-loop at the root, when the chip-firing process starts with (5^n-1)/4 chips at the root.at n=6A378728