Sequences

Numbers whose base-12 representation has the same nonzero number of 1's and 9's.

Numbers whose base-12 representation has the same nonzero number of 1's and 10's.

Numbers whose base-12 representation has the same nonzero number of 1's and 11's.

Numbers whose base-12 representation has the same nonzero number of 2's and 3's.

Numbers whose base-12 representation has the same nonzero number of 2's and 4's.

Solution to a "self-describing sequence" puzzle of Raphael Robinson.

Solution to a "self-describing sequence" puzzle of Raphael Robinson.

Number of 2n-step self-avoiding closed walks on first octant of 3-dimensional cubic lattice, passing through origin.

Second column of Jabotinsky-triangle A038455 related to A006963.

Erroneous version of A008296.

Triangle of Lehmer-Comtet numbers of 2nd kind.

Number of n X n Young tableaux.

a(n) = n^2*(n^2+3)/4.

Numbers n such that there are equal numbers of 0's and 1's in first n digits of binary representation of Pi.

Number of planar simply-connected mono-q-polyhexes for q=5.

Number of planar simply-connected mono-q-polyhexes for q=4.

Number of planar simply-connected mono-q-polyhexes for q=3.

Number of planar simply-connected mono-q-polyhexes for q=2.

Mono-3-catahelicenes.

Mono-3-catahelicenes.

Mono-2-catahelicenes.

Mono-2-catahelicenes.

Mono-2-catahelicenes.

Fixed point of "n -> n/2 or (n-1)/2 until result is prime".

Fixed point of "n -> n/2 or (n+1)/2 until result is prime".

Number of steps to fixed point of "n -> n/2 or (n-1)/2 until result is prime".

Number of steps to fixed point of "n -> n/2 or (n+1)/2 until result is prime".

Fixed point of "k -> k/2 or (k-1)/2 until result is prime", starting with prime(n)-1.

Fixed point of "k -> k/2 or (k-1)/2 until result is prime", starting with prime(n)+1.

Fixed point of "k -> k/2 or (k+1)/2 until result is prime", starting with prime(n)-1.

Fixed point of "k -> k/2 or (k+1)/2 until result is prime", starting with prime(n)+1.

Number of steps to fixed point of "k -> k/2 or (k-1)/2 until result is prime", starting with prime(n)-1.

Number of steps to fixed point of "k -> k/2 or (k-1)/2 until result is prime", starting with prime(n)+1.

Number of steps to fixed point of "k -> k/2 or (k+1)/2 until result is prime", starting with prime(n)-1.

Number of steps to fixed point of "k -> k/2 or (k+1)/2 until result is prime", starting with prime(n)+1.

Third column of Jabotinsky-triangle A038455 related to A006963.

Related to A000032 (Lucas numbers): (n-1)!*L(n).

Number of n-step self-avoiding paths on the first octant of a 3-dimensional cubic lattice, starting at the origin.

a(n) = phi(n)+1.

Prime reached by iterating f(x) = phi(x)+1 on n.

Number of iterations of f(x) = phi(x)+1 on n required to reach a prime.

Becomes prime after n iterations of f(x) = phi(x)+1 (least inverse of A039651).

a(0) = 0; for n > 0, a(n) = sigma(n)-1.

a(n) = prime reached by iterating f(x) = sigma(x)-1 starting at n, or -1 if no prime is ever reached.

Number of iterations of f(x) = sigma(x)-1 applied to n required to reach a prime, or -1 if no prime is ever reached.

Becomes prime after n iterations of f(x) = sigma(x)-1 (least inverse of A039655).

Number of digits in all (2n+1)-digit palindromic primes.

Related to enumeration of edge-rooted catafusenes.

Erroneous version of A039919.

Related to enumeration of edge-rooted catafusenes.