Indices of pentagonal numbers (A000326) which are also centered square numbers (A001844).

A254709

Indices of pentagonal numbers (A000326) which are also centered square numbers (A001844).

Terms

    a(0) =1a(1) =2a(2) =10a(3) =25a(4) =137a(5) =346a(6) =1906a(7) =4817a(8) =26545a(9) =67090a(10) =369722a(11) =934441a(12) =5149561a(13) =13015082a(14) =71724130a(15) =181276705a(16) =998988257a(17) =2524858786a(18) =13914111466a(19) =35166746297a(20) =193798572265a(21) =489809589370

External references