Totient of the Woodall numbers (A003261), n*2^n -1.

Terms

a(0) =1a(1) =6a(2) =22a(3) =36a(4) =104a(5) =382a(6) =712a(7) =1936a(8) =4320a(9) =6824a(10) =15012a(11) =46992a(12) =79344a(13) =183000a(14) =421008a(15) =480000a(16) =1453784a(17) =4658784a(18) =8877792a(19) =20958480a(20) =38887680a(21) =61284600a(22) =110250264a(23) =388201176a(24) =719023536a(25) =1734432480a(26) =2889658368a(27) =4745378304a(28) =10350643968a(29) =32212254718