Pentagonal numbers for which the sum of the digits is also a pentagonal number.

Terms

a(0) =0a(1) =1a(2) =5a(3) =651a(4) =1335a(5) =2262a(6) =3432a(7) =3577a(8) =6501a(9) =8400a(10) =8626a(11) =10542a(12) =10795a(13) =15862a(14) =18760a(15) =21540a(16) =25285a(17) =28912a(18) =32340a(19) =32782a(20) =45850a(21) =50142a(22) =50692a(23) =55200a(24) =60501a(25) =72490a(26) =91390a(27) =98945a(28) =104412a(29) =112477