Pentagonal numbers (A000326) in which parity of digits alternates.

Terms

a(0) =1a(1) =5a(2) =12a(3) =70a(4) =92a(5) =145a(6) =210a(7) =852a(8) =925a(9) =2147a(10) =2501a(11) =3290a(12) =3432a(13) =3876a(14) =4187a(15) =4347a(16) =6305a(17) =6501a(18) =12105a(19) =12927a(20) =25676a(21) =27270a(22) =27676a(23) =45850a(24) =58707a(25) =69230a(26) =69876a(27) =70525a(28) =76501a(29) =78547