Least number k>1 such that centered n-gonal number n*k(k-1)/2+1 is a perfect square, or 0 if no such k exists.
A145856
Least number k>1 such that centered n-gonal number n*k(k-1)/2+1 is a perfect square, or 0 if no such k exists.
Terms
- a(0) =3a(1) =0a(2) =2a(3) =4a(4) =3a(5) =8a(6) =16a(7) =2a(8) =17a(9) =9a(10) =15a(11) =5a(12) =6a(13) =16a(14) =2a(15) =3a(16) =6a(17) =0a(18) =7a(19) =4a(20) =3a(21) =40a(22) =7a(23) =2a(24) =22a(25) =8a(26) =111a(27) =4a(28) =16a(29) =8
External references
- oeis: A145856