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A135416 a(n) = A036987(n)*(n+1)/2. 30
1, 0, 2, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Guy Steele defines a family of 36 integer sequences, denoted here by GS(i,j) for 1 <= i, j <= 6, as follows. a[1]=1; a[2n] = i-th term of {0,1,a[n],a[n]+1,2a[n],2a[n]+1}; a[2n+1] = j-th term of {0,1,a[n],a[n]+1,2a[n],2a[n]+1}. The present sequence is GS(1,5).

The full list of 36 sequences:

GS(1,1) = A000007

GS(1,2) = A000035

GS(1,3) = A036987

GS(1,4) = A007814

GS(1,5) = A135416 (the present sequence)

GS(1,6) = A135481

GS(2,1) = A135528

GS(2,2) = A000012

GS(2,3) = A000012

GS(2,4) = A091090

GS(2,5) = A135517

GS(2,6) = A135521

GS(3,1) = A036987

GS(3,2) = A000012

GS(3,3) = A000012

GS(3,4) = A000120

GS(3,5) = A048896

GS(3,6) = A038573

GS(4,1) = A135523

GS(4,2) = A001511

GS(4,3) = A008687

GS(4,4) = A070939

GS(4,5) = A135529

GS(4,6) = A135533

GS(5,1) = A048298

GS(5,2) = A006519

GS(5,3) = A080100

GS(5,4) = A087808

GS(5,5) = A053644

GS(5,6) = A000027

GS(6,1) = A135534

GS(6,2) = A038712

GS(6,3) = A135540

GS(6,4) = A135542

GS(6,5) = A054429

GS(6,6) = A003817

(with a(0)=1): Moebius transform of A038712.

LINKS

Table of n, a(n) for n=1..105.

FORMULA

G.f.: sum{k>=1, 2^(k-1)*x^(2^k-1) }.

Recurrence: a(2n+1) = 2a(n), a(2n) = 0, starting a(1) = 1.

MAPLE

GS:=proc(i, j, M) local a, n; a:=array(1..2*M+1); a[1]:=1;

for n from 1 to M do

a[2*n] :=[0, 1, a[n], a[n]+1, 2*a[n], 2*a[n]+1][i];

a[2*n+1]:=[0, 1, a[n], a[n]+1, 2*a[n], 2*a[n]+1][j];

od: a:=convert(a, list); RETURN(a); end;

GS(1, 5, 200):

MATHEMATICA

i = 1; j = 5; Clear[a]; a[1] = 1; a[n_?EvenQ] := a[n] = {0, 1, a[n/2], a[n/2]+1, 2*a[n/2], 2*a[n/2]+1}[[i]]; a[n_?OddQ] := a[n] = {0, 1, a[(n-1)/2], a[(n-1)/2]+1, 2*a[(n-1)/2], 2*a[(n-1)/2]+1}[[j]]; Array[a, 105] (* Jean-Fran├žois Alcover, Sep 12 2013 *)

CROSSREFS

Equals A048298(n+1)/2. Cf. A036987, A182660.

Sequence in context: A076260 A245527 A287871 * A134309 A051516 A236799

Adjacent sequences:  A135413 A135414 A135415 * A135417 A135418 A135419

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, based on a message from Guy Steele and Don Knuth, Mar 01 2008

EXTENSIONS

Formulae and comments by Ralf Stephan, Jun 20 2014

STATUS

approved

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Last modified February 21 12:27 EST 2018. Contains 299411 sequences. (Running on oeis4.)