a(n) is the smallest number which can be represented as the sum of four distinct nonzero n-gonal numbers in exactly n ways, or -1 if no such number exists.

A374274

a(n) is the smallest number which can be represented as the sum of four distinct nonzero n-gonal numbers in exactly n ways, or -1 if no such number exists.

Terms

    a(0) =47a(1) =142a(2) =344a(3) =652a(4) =834a(5) =1542a(6) =2263a(7) =3090a(8) =4792a(9) =4570a(10) =5844a(11) =8480a(12) =9571a(13) =10542a(14) =15892a(15) =18202a(16) =19587a(17) =23166a(18) =26732a(19) =32040a(20) =36371a(21) =39730a(22) =44709a(23) =52940a(24) =55141a(25) =60362a(26) =67705a(27) =79624a(28) =86906a(29) =89266

External references