Second differences of seventh powers (A001015).

Terms

a(0) =1a(1) =126a(2) =1932a(3) =12138a(4) =47544a(5) =140070a(6) =341796a(7) =730002a(8) =1412208a(9) =2531214a(10) =4270140a(11) =6857466a(12) =10572072a(13) =15748278a(14) =22780884a(15) =32130210a(16) =44327136a(17) =59978142a(18) =79770348a(19) =104476554a(20) =134960280a(21) =172180806a(22) =217198212a(23) =271178418