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A127971 a(n) = fusc(n+1) + (1-(-1)^n)/2, fusc = A002487. 2
1, 2, 2, 2, 3, 3, 3, 2, 4, 4, 5, 3, 5, 4, 4, 2, 5, 5, 7, 4, 8, 6, 7, 3, 7, 6, 8, 4, 7, 5, 5, 2, 6, 6, 9, 5, 11, 8, 10, 4, 11, 9, 13, 6, 12, 8, 9, 3, 9, 8, 12, 6, 13, 9, 11, 4, 10, 8, 11, 5, 9 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Row sums of A127970.

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = (1-(-1)^n)/2 + Sum_{k=0..floor(n/2), mod(C(n-k,k),2).

MATHEMATICA

Table[Sum[Mod[Binomial[n-k, k], 2], {k, 0, Floor[n/2]}] + (1-(-1)^n)/2, {n, 0, 50}] (* G. C. Greubel, May 04 2018 *)

PROG

(PARI) for(n=0, 50, print1((1-(-1)^n)/2 + sum(k=0, floor(n/2), lift(Mod( binomial(n-k, k), 2))), ", ")) \\ G. C. Greubel, May 04 2018

(MAGMA) [(1-(-1)^n)/2 + (&+[Binomial(n-k, k) mod 2: k in [0..Floor(n/2)]]) : n in [0..50]]; // G. C. Greubel, May 04 2018

CROSSREFS

Sequence in context: A295284 A292995 A037179 * A319290 A230516 A192688

Adjacent sequences:  A127968 A127969 A127970 * A127972 A127973 A127974

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Feb 09 2007

STATUS

approved

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Last modified October 22 14:44 EDT 2019. Contains 328318 sequences. (Running on oeis4.)