Let S_k denote the sequence of numbers j such that A001222(j) - A001221(j) = k. Then a(n) is the n-th term of S_n.

A261256

Let S_k denote the sequence of numbers j such that A001222(j) - A001221(j) = k. Then a(n) is the n-th term of S_n.

Terms

    a(0) =4a(1) =24a(2) =72a(3) =160a(4) =432a(5) =896a(6) =2592a(7) =5632a(8) =12800a(9) =26624a(10) =61440a(11) =124416a(12) =278528a(13) =622592a(14) =1376256a(15) =2949120a(16) =5971968a(17) =12058624a(18) =25690112a(19) =60817408a(20) =130023424a(21) =262144000a(22) =528482304a(23) =1107296256a(24) =2264924160a(25) =4586471424a(26) =9395240960a(27) =19864223744a(28) =40265318400a(29) =83751862272

External references