Number of (undirected) paths in the n-dipyramidal graph.

Terms

a(0) =3a(1) =26a(2) =111a(3) =396a(4) =1235a(5) =3414a(6) =8463a(7) =19064a(8) =39555a(9) =76530a(10) =139535a(11) =241860a(12) =401427a(13) =641774a(14) =993135a(15) =1493616a(16) =2190467a(17) =3141450a(18) =4416303a(19) =6098300a(20) =8285907a(21) =11094534a(22) =14658383a(23) =19132392a(24) =24694275a(25) =31546658a(26) =39919311a(27) =50071476a(28) =62294291a(29) =76913310