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A032187 Shifts left 3 places under "CIJ" (necklace, indistinct, labeled) transform. 1
1, 1, 1, 1, 2, 6, 26, 151, 1093, 9489, 96084, 1111722, 14469388, 209234595, 3328056991, 57746229265, 1085448899206, 21972175778646, 476535125344462, 11024061833485335, 270965694793159153, 7051933526740491393, 193723061625591928384, 5601822117610355927946 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,5
LINKS
FORMULA
a(n) = sum(k=0..n-5, binomial(n-4,k)*a(k+4)*a(n-k-4)) + a(n-3), n>4, a(1)=a(2)=a(3)=a(4)=1. - Vladimir Kruchinin, May 10 2011
E.g.f. A(x) satisfies differential equation A'''(x)=log(1/(1-A(x))), A'(0)=1, A''(0)=1, A'''(0)=1. - Vladimir Kruchinin, Nov 19 2011
PROG
(Maxima)
a(n):=if n=0 then 0 else if n<5 then 1 else sum(binomial(n-4, k)*a(k+4)*a(n-k-4), k, 0, n-5)+a(n-3); /* Vladimir Kruchinin, May 10 2011 */
(PARI)
CIJ(p)={-log(1-p)}
seq(n)={my(p=x+x^2+O(x*x^(n%3))); for(i=1, n\3, p=intformal(1 + intformal(1 + intformal(1 + CIJ(p))))); Vec(serlaplace(p))} \\ Andrew Howroyd, Sep 19 2018
CROSSREFS
Sequence in context: A159311 A000629 A185994 * A003659 A159602 A032271
KEYWORD
nonn,eigen
AUTHOR
EXTENSIONS
Terms a(22) and beyond from Andrew Howroyd, Sep 19 2018
STATUS
approved

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Last modified March 28 04:58 EDT 2024. Contains 371235 sequences. (Running on oeis4.)