login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A247936 Riordan array ((1-2x)/(1-3x), 2x). 0
1, 1, 2, 3, 2, 4, 9, 6, 4, 8, 27, 18, 12, 8, 16, 81, 54, 36, 24, 16, 32, 243, 162, 108, 72, 48, 32, 64, 729, 486, 324, 216, 144, 96, 64, 128, 2187, 1458, 972, 648, 432, 288, 192, 128, 256, 6561, 4374, 2916, 1944, 1296, 864, 576, 384, 256, 512, 19683, 13122 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Mirror of A153279.

LINKS

Table of n, a(n) for n=0..56.

FORMULA

Sum_{k, 0<=k<=n} T(n,k) = 3^n = A000244(n).

T(n,k) = A133494(n-k)*2^k.

T(2n,n) = A167747(n).

EXAMPLE

Triangle begins:

1

1, 2

3, 2, 4

9, 6, 4, 8

27, 18, 12, 8, 16

81, 54, 36, 24, 16, 32

243, 162, 108, 72, 48, 32, 64

Production matrix begins:

1, 2

1, 0, 2

1, 0, 0, 2

1, 0, 0, 0, 2

1, 0, 0, 0, 0, 2

1, 0, 0, 0, 0, 0, 2

1, 0, 0, 0, 0, 0, 0, 2

CROSSREFS

Cf. A000079, A000244, A133494, A153279, A167747.

Sequence in context: A059576 A274803 A274749 * A231150 A274858 A207997

Adjacent sequences:  A247933 A247934 A247935 * A247937 A247938 A247939

KEYWORD

nonn,tabl

AUTHOR

Philippe Deléham, Sep 26 2014

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 5 18:00 EDT 2021. Contains 346488 sequences. (Running on oeis4.)