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A061549 Denominator of probability that there is no error when average of n numbers is computed, assuming errors of +1, -1 are possible and they each occur with p=1/4. 7
1, 8, 128, 1024, 32768, 262144, 4194304, 33554432, 2147483648, 17179869184, 274877906944, 2199023255552, 70368744177664, 562949953421312, 9007199254740992, 72057594037927936, 9223372036854775808, 73786976294838206464, 1180591620717411303424, 9444732965739290427392 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jul 06 2009: (Start)

We observe that b(n) = ln(a(n))/ln(2) = A120738(n). Furthermore c(n+1) = b(n+1)-b(n) = A090739(n+1) and c(n+1)-3 = A007814(n+1) for n>=0.

(End)

REFERENCES

Kozelka, Robert M. "Grade Point Averages and the Central Limit Theorem." American Mathematical Monthly. Nov. 1979 (86:9) pp. 773-7.

LINKS

Eric Weisstein's World of Mathematics, Circle Line Picking

Eric Weisstein's World of Mathematics, Gamma Function

FORMULA

a(n) = binomial(2*n-1/2, -1/2).

a(n) are denominators of coefficients of 1/(sqrt(1+x)-sqrt(1-x)) power series - Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 12 2002

a(n)=16^n/A001316(n); - Paul Barry (pbarry(AT)wit.ie), Jun 29 2006

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jul 06 2009: (Start)

a(n) = denom((4*n)!/(2^(4*n)*(2*n)!^2))

(End)

EXAMPLE

For n=1, the binomial(2*n-1/2, -1/2) yields the term 3/8. The denominator of this term is 8, which is the second term of the sequence.

MAPLE

seq(denom(binomial(2*n-1/2, -1/2)), n=1..20);

CROSSREFS

Cf. A061548.

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jul 06 2009: (Start)

Equals abs(A067624(n)/A117972(n))

Bisection of A046161.

Appears in A162448.

(End)

Sequence in context: A171755 A204194 A093586 * A105094 A036294 A133680

Adjacent sequences:  A061546 A061547 A061548 * A061550 A061551 A061552

KEYWORD

nonn,frac,easy

AUTHOR

Leah Schmelzer (leah2002(AT)mit.edu), May 16 2001

EXTENSIONS

More terms from Asher Auel (asher.auel(AT)reed.edu), May 20 2001

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Last modified February 17 18:41 EST 2012. Contains 206074 sequences.