Least number k > 0 such that k*2^n+1 is a cube.

Terms

a(0) =7a(1) =13a(2) =31a(3) =91a(4) =307a(5) =1123a(6) =4291a(7) =16771a(8) =66307a(9) =263683a(10) =1051651a(11) =4200451a(12) =16789507a(13) =67133443a(14) =268484611a(15) =1073840131a(16) =4295163907a(17) =17180262403a(18) =68720263171a(19) =274879479811