# A000765 (b-file synthesized from sequence entry) 0 1 1 4 2 36 3 308 4 2764 5 25404 6 237164 7 2237948 8 21286548 9 203701772 10 1958748676 11 18908954324 12 183135542956 13 1778581016076 14 17314029758828 15 168891863875652