21229

Appears in sequences

• Number of symmetrical planar partitions of n (planar partitions (A000219) that when regarded as 3-D objects have just one symmetry plane).at n=37A000784
• Number of n-node forests not determined by their spectra.at n=15A006611
• Expansion of 1/(1+x^2-2*x^3).at n=32A077912
• Expansion of 1/(1+x^2+2*x^3).at n=32A077963
• Zeroless analog of tribonacci numbers.at n=23A371911