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Search: id:A062112
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A062112 a(0)=0; a(1)=1; a(n) = a(n-1) + (3+(-1)^n)*a(n-2)/2 +0
3
0, 1, 1, 2, 4, 6, 14, 20, 48, 68, 164, 232, 560, 792, 1912, 2704, 6528, 9232, 22288, 31520, 76096, 107616, 259808, 367424, 887040, 1254464, 3028544, 4283008, 10340096, 14623104, 35303296, 49926400, 120532992, 170459392, 411525376 (list; graph; listen)
OFFSET

0,4

LINKS

Harry J. Smith, Table of n, a(n) for n=0,...,200

FORMULA

G.f.: x(1+x-2x^2)/(1-4x^2+2x^4).

EXAMPLE

a(4) = a(3) + 2* a(2) = 2+ 2 = 4

PROGRAM

(PARI) { for (n=0, 200, if (n>1, a=a1 + (3 + (-1)^n)*a2/2; a2=a1; a1=a, if (n==0, a=a2=0, a=a1=1)); write("b062112.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 01 2009]

CROSSREFS

A007068.

a(2n)=A007070(n+1). a(2n+1)=A006012(n).

Sequence in context: A095698 A064409 A032353 this_sequence A084685 A151794 A058059

Adjacent sequences: A062109 A062110 A062111 this_sequence A062113 A062114 A062115

KEYWORD

easy,nonn

AUTHOR

Olivier Gerard (olivier.gerard(AT)gmail.com), Jun 05 2001

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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