

A017817


a(0)=1, a(1)=a(2)=0, a(3)=1; a(n)=a(n3)+a(n4).


14



1, 0, 0, 1, 1, 0, 1, 2, 1, 1, 3, 3, 2, 4, 6, 5, 6, 10, 11, 11, 16, 21, 22, 27, 37, 43, 49, 64, 80, 92, 113, 144, 172, 205, 257, 316, 377, 462, 573, 693, 839, 1035, 1266, 1532, 1874, 2301, 2798, 3406, 4175, 5099, 6204, 7581, 9274, 11303, 13785, 16855, 20577, 25088
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OFFSET

0,8


COMMENTS

Number of permutations satisfying k<=p(i)i<=r and p(i)i not in I, i=1..n, with k=1, r=3, I={0,1}. [Vladimir Baltic, Mar 07 2012]
Number of compositions (ordered partitions) of n into parts 3 and 4.


LINKS

Table of n, a(n) for n=0..57.
Vladimir Baltic, On the number of certain types of strongly restricted permutations, Applicable Analysis and Discrete Mathematics 4 (2010), 119135
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 484
E. Wilson, The Scales of Mt. Meru
Index entries for twoway infinite sequences
Index to sequences with linear recurrences with constant coefficients, signature (0,0,1,1).


FORMULA

G.f.: 1/(1x^3x^4).
a(n)/a(n1) tends to A060007 .  Gary W. Adamson, Oct 22 2006


MATHEMATICA

a=b=c=0; d=1; lst={d}; Do[AppendTo[lst, e=a+b]; a=b; b=c; c=d; d=e, {n, 0, 5!}]; lst [From Vladimir Joseph Stephan Orlovsky, May 28 2010]


PROG

(PARI) a(n)=polcoeff(if(n<0, (1+x)/(1+xx^4), 1/(1x^3x^4))+x*O(x^abs(n)), abs(n))


CROSSREFS

A003269(n)=a(4n)(1)^n.
Sequence in context: A247749 A247367 A127838 * A189913 A240807 A053268
Adjacent sequences: A017814 A017815 A017816 * A017818 A017819 A017820


KEYWORD

nonn


AUTHOR

N. J. A. Sloane.


EXTENSIONS

More terms from Klaus Strassburger (strass(AT)ddfi.uniduesseldorf.de), Dec 17 1999


STATUS

approved



