Sequences

a(n) = n^2*(n^2 - 1)/6.

Truncated triangular numbers (of form n*(n-3)/2 - k^2+k*n+1 for 1<=k<n).

Order of simple Chevalley group F_4(q), q = prime power.

Order of simple Chevalley group G_2 (q), q = prime power.

Order of universal twisted Chevalley group 2_E_6 (q), q = prime power.

Order of simple twisted Chevalley group 2_E_6 (q), q = prime power.

Numbers that are the sum of 3 positive cubes in more than one way.

Numbers k such that 4*k = (k written backwards), k > 0.

Numbers k such that k written backwards is a nontrivial multiple of k.

Let j = | i - i_written_backwards |, k = j + j_written_backwards; then k is in this sequence.

Coordination sequence for lattice {E_7}*.

Crystal ball sequence for lattice {E_7}*.

Euler's family of solutions to n = x^4 + y^4 = z^4 + w^4.

Harmonic Molien series for Conway group Con.0.

Molien series for Conway group Con.0.

Number of uniquely agreeing sequences.

Number of increasing sequences of star chain type with maximal element n.

Number of increasing sequences of addition chain type with maximal element n.

Number of increasing sequences of Goldbach type with maximal element n.

Number of compositions (p_1, p_2, p_3, ...) of n with 1 <= p_i <= i for all i.

Expansion of (2/(1+sqrt(1-36*x)))^(1/3).

Number of increasing sequences of Goldbach type of length n; a(0) = 1 by convention.

Number of strictly increasing addition chains of length n.

Number of tournament sequences: sequences (a_1, a_2, ..., a_n) with a_1 = 1 such that a_i < a_{i+1} <= 2*a_i for all i.

If 2n = Sum 2^e(k) then a(n) = Sum e(k)^2.

Expansion of (1 - 2*x -x^4)/(1 - 2*x)^2 in powers of x.

a(n) = Sum_{k=0..n} T(k) where T(n) are the tribonacci numbers A000073.

Degrees of irreducible representations of group U3(3).

Degrees of irreducible representations of group U3(4).

Degrees of irreducible representations of group U3(5).

Degrees of irreducible representations of group U3(7).

Degrees of irreducible representations of group U3(8).

Degrees of irreducible representations of group U3(9).

Degrees of irreducible representations of group U3(11).

Degrees of irreducible representations of group U4(2).

Degrees of irreducible representations of group U4(3).

Degrees of irreducible representations of group U5(2).

Degrees of irreducible representations of group U6(2).

Triangle read by rows of partial sums of binomial coefficients: T(n,k) = Sum_{i=0..k} binomial(n,i) (0 <= k <= n); also dimensions of Reed-Muller codes.

Increasing length runs of consecutive composite numbers (starting points).

Array read by columns: number of partitions of n into parts of 2 kinds.

Leading digit of 2^n.

a(n) is the leading digit of the n-th triangular number, n*(n+1)/2.

Final digit of triangular number n*(n+1)/2.

Triangle of central factorial numbers |t(2n,2n-2k)| read by rows.

Triangle of central factorial numbers |4^k t(2n+1,2n+1-2k)| read by rows (n>=0, k=0..n).

Triangle of central factorial numbers T(2*n,2*n-2*k), k >= 0, n >= 1 (in Riordan's notation).

Triangle of central factorial numbers 4^k T(2n+1, 2n+1-2k).

Final digit of squares: a(n) = n^2 mod 10.

Final digit of cubes: n^3 mod 10.