Sequences

Number of nontrivial disconnected complements of Steinhaus graphs on n nodes.

Number of bipartite Steinhaus graphs on n nodes.

a(n) is smallest number != a(j) + a(k), j < k and a(1) = 1, a(2) = 4.

a(n) is smallest number != a(j) + a(k), j < k and a(1) = 1, a(2) = 6.

a(n) is smallest number larger than a(n-1) and not = a(j) + a(k), j < k.

a(n) = 2^(n-1)*( 2^n + (-1)^n ).

a(n) is smallest number which is uniquely of the form a(j) + a(k) with 1 <= j < k < n and a(1) = 1, a(2) = 4.

a(n) is smallest number which is uniquely of the form a(j) + a(k) with 1 <= j < k < n and a(1) = 1, a(2) = 5.

a(n) is smallest number which is uniquely a(j)+a(k), j<k.

a(n) is smallest number which is uniquely a(j) + a(k), j < k.

a(n) is smallest number which is uniquely a(j)+a(k).

Decimal expansion of Bohr radius (meters).

Decimal expansion of electron mass (mass units).

Decimal expansion of fine-structure constant alpha.

a(n) = 2^(n-1)*(2^n - (-1)^n).

Decimal expansion of neutron mass (mass units).

Decimal expansion of the Planck constant h (Joule * second).

Decimal expansion of proton mass (mass units).

Decimal expansion of the SI unit c (speed of light in vacuum), c = 299792458 meters/second.

Numbers that are not the sum of 3 pentagonal numbers.

Smallest number with 2n divisors.

a(n) = min { p +- q : p +- q > 1 and p*q = Product_{k=1..n-1} a(k) }.

Number of (undirected) Hamiltonian paths in the n-ladder graph K_2 X P_n.

a(n) = 2^(n-1)*(2^n - (-1)^n)/3.

Number of n-digit reversible primes (or emirps) with distinct digits.

Number of Hamiltonian paths in P_3 X P_n.

Number of genealogical 1-2 rooted trees of height n.

a(n+1) = a(n)-a(1)a(2)...a(n-1), if n>0. a(0)=1, a(1)=2.

a(n) = 3*a(n-1) + a(n-2), with a(1)=1 and a(2)=4.

Number of Hamiltonian paths in K_3 X P_n.

Number of spanning trees in K_3 X P_n.

Number of spanning trees with degrees 1 and 3 in K_3 X P_2n.

Number of trees on n labeled vertices with degree at most 3.

Number of 2-factors in P_4 X P_n.

Incomplete version of A000053.

Number of Hamiltonian paths in P_4 X P_n.

Number of spanning trees in P_4 X P_n.

Duplicate of A006253.

Number of 2-factors in C_4 X P_n.

Number of Hamiltonian cycles in C_4 X P_n.

Expansion of tan(x /cosh(x)).

Expansion of e.g.f. exp(x)/cos(x).

Expansion of tan(x)/cosh(x).

Expansion of e.g.f. cos(log(1+x)).

Expansion of log(1+sinh(x)).

E.g.f. tan(sin(x)) (odd powers only).

Expansion of e.g.f. sin(tan(x)), zeros omitted.

Expansion of e.g.f. log(1 + tan(x)).

Expansion of tan(log(1+x)).

E.g.f. cos(sin(x)) (even powers only).