Number of ways n-th repdigit number, A010785(n), can be expressed as a polygonal number.

Terms

a(0) =2a(1) =2a(2) =2a(3) =2a(4) =3a(5) =2a(6) =2a(7) =3a(8) =2a(9) =3a(10) =3a(11) =2a(12) =4a(13) =5a(14) =2a(15) =3a(16) =3a(17) =4a(18) =3a(19) =4a(20) =3a(21) =4a(22) =5a(23) =3a(24) =3a(25) =3a(26) =3a(27) =2a(28) =3a(29) =3