Doubly pentagonal numbers: a(n) = n*(3*n-2)*(3*n-1)*(3*n+1)/8.

Terms

a(0) =0a(1) =1a(2) =35a(3) =210a(4) =715a(5) =1820a(6) =3876a(7) =7315a(8) =12650a(9) =20475a(10) =31465a(11) =46376a(12) =66045a(13) =91390a(14) =123410a(15) =163185a(16) =211876a(17) =270725a(18) =341055a(19) =424270a(20) =521855a(21) =635376a(22) =766480a(23) =916895a(24) =1088430a(25) =1282975a(26) =1502501a(27) =1749060a(28) =2024785a(29) =2331890