Odd pentagonal pyramidal numbers.

Terms

a(0) =1a(1) =75a(2) =405a(3) =1183a(4) =2601a(5) =4851a(6) =8125a(7) =12615a(8) =18513a(9) =26011a(10) =35301a(11) =46575a(12) =60025a(13) =75843a(14) =94221a(15) =115351a(16) =139425a(17) =166635a(18) =197173a(19) =231231a(20) =269001a(21) =310675a(22) =356445a(23) =406503a(24) =461041a(25) =520251a(26) =584325a(27) =653455a(28) =727833a(29) =807651