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A023365 a(n) = 2^(3^(n-1)). 2
2, 8, 512, 134217728, 2417851639229258349412352, 14134776518227074636666380005943348126619871175004951664972849610340958208 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n+1) = a(n) converted to base 8 from base 2 (written in base 10).

Number of disjunctive-normal forms of n-1 variables (either with x, or x-negated or without x). - Labos E. (labos(AT)ana.sote.hu), Jul 24 2003

a(n)*Psi(3^n,x), with the (monic) minimal polynomial Psi(3^n,x) of cos(2*Pi/3^n), becomes an integer polynomial with coefficient 1 of x^0.

  E.g., 8*Psi(9,x)=8*(x^3 - (3/4)*x + 1/8) = 8*x^3 - 6*x + 1.

  See A181875/A181876, A181877 and the W. Lang link under A181875. Wolfdieter Lang, Feb 24 2011.

REFERENCES

W. van der Aalst, J. Buijs and B. van Dongen, Towards Improving the Representational Bias of Process Mining, 2012; http://wwwis.win.tue.nl/~wvdaalst/publications/p655.pdf. - From N. J. A. Sloane, Feb 03 2013

LINKS

Table of n, a(n) for n=1..6.

FORMULA

a(n) = a(n-1)^3.

CROSSREFS

a(n) = A000079(A000244(n-1)).

Sequence in context: A033542 A098870 A221065 * A013554 A175923 A076985

Adjacent sequences:  A023362 A023363 A023364 * A023366 A023367 A023368

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified May 23 20:41 EDT 2013. Contains 225612 sequences.