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A064405 Number of even entries (A048967) minus the number of odd entries (A001316) in row n of Pascal's triangle (A007318). 3
-1, -2, -1, -4, 1, -2, -1, -8, 5, 2, 3, -4, 5, -2, -1, -16, 13, 10, 11, 4, 13, 6, 7, -8, 17, 10, 11, -4, 13, -2, -1, -32, 29, 26, 27, 20, 29, 22, 23, 8, 33, 26, 27, 12, 29, 14, 15, -16, 41, 34, 35, 20, 37, 22, 23, -8, 41, 26, 27, -4, 29, -2, -1, -64, 61, 58, 59, 52, 61, 54, 55, 40, 65, 58, 59, 44, 61, 46, 47, 16, 73, 66, 67, 52, 69, 54 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..85.

FORMULA

a(n) = sum(k=0, n, (-1)^C(n, k) ); a(2^n) = 2^n-3; a(2^n+1)=2^n-6; more generally there's a sequence z(k) such that for any k>=0 and for 2^n >k, a(2^n+k) = 2^n+z(k); for k=0, 1, 2, 3, 4, 5, 6, 7, 8... z(k) = -3, -6, -5, -12, -3, -10, -9, -24, 1, ... - Benoit Cloitre, Oct 18 2002

a(2n) = a(n) + n, a(2n+1) = 2a(n). - Ralf Stephan, Mar 05 2004

a(n)=-sum{k=0..n, mu(binomial(n, k) mod 2)}; - Paul Barry, Apr 29 2005

MATHEMATICA

Table[ n + 1 - 2Sum[ Mod[ Binomial[ n, k ], 2 ], {k, 0, n} ], {n, 0, 100} ]

PROG

(PARI) a(n)=sum(i=0, n, (-1)^binomial(n, i))

(PARI) a(n)=if(n<1, -1, if(n%2==0, a(n/2)+n/2, 2*a((n-1)/2)))

CROSSREFS

Sequence in context: A218621 A079891 A108738 * A235872 A100762 A059147

Adjacent sequences:  A064402 A064403 A064404 * A064406 A064407 A064408

KEYWORD

easy,sign

AUTHOR

Robert G. Wilson v, Sep 29 2001

STATUS

approved

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Last modified June 12 12:53 EDT 2021. Contains 344947 sequences. (Running on oeis4.)