260046848

Appears in sequences

• Number of subsets of {1,.., n} containing at least one square.at n=27A089888
• Third differences of A129952.at n=25A129955
• Expansion of (1+8x^2+8x^3)/((1-2x)^2*(1+2x+4x^2)).at n=23A168057
• a(1) = 1, a(2) = 2, a(3) = 5, a(4) = 8 and a(5) = 15, a(n) = Sum_{j=1..n-1} a(j).at n=28A257548