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

A374142

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

Terms

    a(0) =8a(1) =617a(2) =8726a(3) =255575a(4) =1339801a(5) =2419165a(6) =9402323a(7) =25764500a(8) =35486953a(9) =144568133a(10) =385495261a(11) =735503569a(12) =638279039a(13) =1183071664a(14) =1571634527a(15) =4449717748a(16) =3584182298a(17) =3871587494a(18) =5693954599a(19) =27084640649a(20) =24205505111a(21) =32489035067a(22) =31973745058a(23) =38935021406a(24) =47570693867a(25) =44749048300a(26) =53075499329

External references