# A017431 (b-file synthesized from sequence entry) 0 2187 1 105413504 2 6103515625 3 78364164096 4 506623120463 5 2207984167552 6 7446353252589 7 20971520000000 8 51676101935731 9 114868566764928 10 235260548044817 11 450766669594624 12 817215093984375 13 1414067010444416