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A242049 Decimal expansion of 'lambda', the Lyapunov exponent characterizing the asymptotic growth rate of the number of odd coefficients in Pascal trinomial triangle mod 2, where coefficients are from (1+x+x^2)^n. 0
4, 2, 9, 9, 4, 7, 4, 3, 3, 3, 4, 2, 4, 5, 2, 7, 2, 0, 1, 1, 4, 6, 9, 7, 0, 3, 5, 5, 1, 9, 9, 2, 2, 3, 2, 3, 3, 2, 4, 0, 6, 5, 0, 1, 1, 5, 8, 9, 3, 0, 4, 6, 1, 7, 0, 4, 0, 2, 7, 6, 0, 7, 2, 5, 7, 4, 2, 8, 3, 3, 7, 2, 8, 3, 1, 3, 9, 8, 1, 0, 5, 6, 8, 4, 5, 6, 3, 4, 9, 0, 0, 7, 4, 8, 4, 7, 4, 2, 5, 3, 6, 6, 5, 4, 3 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..104.

Steven Finch, Pascal Sebah and Zai-Qiao Bai, Odd Entries in Pascal's Trinomial Triangle (arXiv:0802.2654) p. 14.

FORMULA

(1/4)*sum_{k >= 1} (log((1/3)*(2^(k+2) - (-1)^k))/2^k).

EXAMPLE

0.429947433342452720114697035519922323324065011589304617040276...

= log(1.53717671718235794959014032895522160250150809343236...)

MATHEMATICA

digits = 105; lambda = (1/4)*NSum[Log[(1/3)*(2^(k+2) - (-1)^k)]/2^k, {k, 1, Infinity}, WorkingPrecision -> digits + 5, NSumTerms -> 500]; RealDigits[lambda, 10, digits] // First

CROSSREFS

Cf. A242208 (1+x+x^2)^n, A242021 (1+x+x^3)^n, A242022 (1+x+x^2+x^3+x^4)^n, A241002 (1+x+x^4)^n, A242047 (1+x+...+x^4+x^5)^n, A242048 (1+x+...+x^5+x^6)^n.

Sequence in context: A144811 A185654 A228041 * A179398 A233295 A298567

Adjacent sequences:  A242046 A242047 A242048 * A242050 A242051 A242052

KEYWORD

nonn,cons

AUTHOR

Jean-Fran├žois Alcover, Aug 13 2014

STATUS

approved

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Last modified December 15 20:00 EST 2019. Contains 330000 sequences. (Running on oeis4.)