A214318 Replace the word A214317(n) with its position in A007931.

1, 4, 9, 19, 40, 81, 164, 329, 659, 1320, 2641, 5283, 10568, 21137, 42276, 84553, 169107, 338216, 676433, 1352868, 2705737, 5411475, 10822952, 21645905, 43291811, 86583624, 173167249, 346334500, 692669001, 1385338003, 2770676008, 5541352017, 11082704035

Offset

1,2

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Formula

a(n) = A182028(n-1)+2^n-1.

a(n) = 2*a(n-1) + A003842(n-1) for n>1, a(1) = 1. - Alois P. Heinz, Jul 19 2012

Example

A214317(5) = 12112 is the 40th term of A007931, so a(5)=40.

Maple

S:= proc(n) option remember;
      `if`(n<2, [2-n], [S(n-1)[], S(n-2)[]])
    end:
a:= proc(n) option remember; local k;
      for k while nops(S(k))<n do od;
      `if`(n=1, 1, 2*a(n-1) +S(k)[n])
    end:
seq(a(n), n=1..50);  # Alois P. Heinz, Jul 19 2012

Mathematica

nesting = 6; A003849 = Flatten[Nest[{#, #[[1]]}&, {0, 1}, nesting]]; A182028[n_] := FromDigits[Take[A003849, n+1], 2]; a[n_] := A182028[n-1] + 2^n - 1; Table[a[n], {n, 1, Length[A003849]}] (* Jean-François Alcover, Feb 13 2016 *)

Crossrefs

Cf. A003842, A214317, A007931.

Sequence in context: A153894 A372448 A301137 * A300438 A034479 A326340

Adjacent sequences: A214315 A214316 A214317 * A214319 A214320 A214321

Keyword

nonn

Author

N. J. A. Sloane, Jul 12 2012

Extensions

More terms from Alois P. Heinz, Jul 19 2012

Status

approved