a(n) is the smallest number which can be represented as the sum of two distinct nonzero n-gonal numbers in exactly n ways, or -1 if no such number exists.
A374144
a(n) is the smallest number which can be represented as the sum of two distinct nonzero n-gonal numbers in exactly n ways, or -1 if no such number exists.
Terms
- a(0) =81a(1) =1105a(2) =205427a(3) =483031a(4) =9402323a(5) =6232341a(6) =79324200a(7) =768459127a(8) =2265692766a(9) =2413112833a(10) =6737406626a(11) =150437989675a(12) =45319359337a(13) =15140186701
External references
- oeis: A374144