a(n) is the smallest nonnegative integer k where exactly n pairs of positive integers (x, y) exist such that x^2 + 7*y^2 = k.
A374159
a(n) is the smallest nonnegative integer k where exactly n pairs of positive integers (x, y) exist such that x^2 + 7*y^2 = k.
Terms
- a(0) =0a(1) =8a(2) =32a(3) =128a(4) =352a(5) =704a(6) =1408a(7) =2816a(8) =5632a(9) =11264a(10) =16192a(11) =45056a(12) =32384a(13) =123904a(14) =64768a(15) =178112a(16) =129536a(17) =2883584a(18) =259072a(19) =1982464a(20) =469568a(21) =712448a(22) =1036288a(23) =184549376a(24) =939136a(25) =21551552a(26) =4145152a(27) =2849792a(28) =1878272
External references
- oeis: A374159