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

Author

N. J. A. Sloane, Jul 12 2012

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Cf. A003842, A214317, A007931.

Programs

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))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 *)

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

Extensions

More terms from Alois P. Heinz, Jul 19 2012