3966480

Appears in sequences

• Number of labeled n-node 4-valent graphs containing a loop.at n=9A058836
• Triangle read by rows, related to A055129 (repunits in base k).at n=52A107893
• a(n) = 1*2*3*4*5*6*7*8*9 + 10*11*12*13*14*15*16*17*18 + 19*20*21*22*23*24*25*26*27 + ... + (up to n).at n=14A319211
• Number of essentially parallel oriented series-parallel networks with n labeled elements and without multiple unit elements in parallel.at n=7A339300