Numbers of quasi-pyramid polycubes of a given volume (number of atomic cells).

Terms

a(0) =3a(1) =9a(2) =23a(3) =47a(4) =91a(5) =169a(6) =291a(7) =494a(8) =815a(9) =1295a(10) =2043a(11) =3155a(12) =4775a(13) =7165a(14) =10599a(15) =15458a(16) =22455a(17) =32145a(18) =45659a(19) =64519a(20) =90247a(21) =125493a(22) =173515a(23) =238153a(24) =325423a(25) =442169a(26) =597575a(27) =804203a(28) =1077283a(29) =1436593