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A131721 Overlay of Pell companion numbers: a(n)=A001333(n)+A001333(n-6). 0
1, 1, 3, 7, 17, 41, 100, 240, 580, 1400, 3380, 8160, 19700, 47560, 114820, 277200, 669220, 1615640, 3900500, 9416640, 22733780, 54884200, 132502180, 319888560, 772279300, 1864447160, 4501173620, 10866794400, 26234762420, 63336319240 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..29.

Index entries for linear recurrences with constant coefficients, signature (2,1)

FORMULA

a(n) = A001333(n), n<6. a(n) = A001333(n)+A001333(n-6) = 20*A000129(n-3), n>=6.

O.g.f.: (x-1)(x^2+1)(x^4-x^2+1)/(-1+2x+x^2). - R. J. Mathar, Jul 16 2008

CROSSREFS

Cf. A131710.

Sequence in context: A078057 A089742 A187258 * A259855 A058351 A244782

Adjacent sequences:  A131718 A131719 A131720 * A131722 A131723 A131724

KEYWORD

nonn,easy

AUTHOR

Paul Curtz, Sep 15 2007

EXTENSIONS

Edited and extended by R. J. Mathar, Jul 16 2008

STATUS

approved

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Last modified November 18 01:20 EST 2018. Contains 317279 sequences. (Running on oeis4.)