743040

Appears in sequences

• Expansion of Eisenstein series E_4(q) (alternate convention E_2(q)); theta series of E_8 lattice.at n=14A004009
• Spherical growth series for pair of groups, one Gromov hyperbolic, the other not.at n=4A063809
• Coefficients in q-expansion of E_2^2, where E_2 is the Eisenstein series shown in A006352.at n=15A281374
• E.g.f.: exp(-(x + x^2/2 + x^3/3 + x^4/4)).at n=12A334570
• a(0) = a(1) = 1; a(n) = 2 * Sum_{k=0..n-2} a(k) * a(n-k-2).at n=15A354733