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A272694 a(n) = (c(n)+f(c(n)))/2, where c() = A272693() and f(k) = sign(k)*(k mod 2). 1
0, -1, -1, -3, -2, -2, -2, 0, 3, 1, -2, -3, -4, -3, 1, 5, 2, -3, -5, -5, -2, 3, 6, 3, -5, -11, -6, 3, 7, 5, -3, -10, -9, -2, 8, 8, 1, -8, -11, -6, 6, 10, 5, -6, -13, -9, 1, 11, 8, -3, -11, -11, -2, 9, 12, 3, -11, -17, -8, 9, 18, 9, -11, -23, -12, 9, 19, 11, -9, -22, -15, 4, 20, 14, -6, -20, -17, 2, 19, 17 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Created in an attempt to simplify the definition of A108618.

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 0..10000

MAPLE

M:=1000;

a:=Array(0..M, 0); # A108618 (with different offset)

b:=Array(0..M, 0); # A108619 (with different offset)

c:=Array(0..M, 0); # A272693

f:=n->sign(n)*(n mod 2);

a[0]:=0; b[0]:=0; c[0]:=0;

for n from 1 to M do

b[n]:=1+(a[n-1]+b[n-1])/2;

a[n]:=1+c[n-1]+f(c[n-1])+3*f(b[n]-1);

c[n]:=(a[n]-3*b[n])/2;

od:

[seq(a[n], n=0..M)];

[seq(b[n], n=0..M)];

[seq(c[n], n=0..M)];

[seq((c[n]+f(c[n]))/2, n=0..M)]; # A272694

CROSSREFS

Cf. A108618, A108619, A272693.

Sequence in context: A098054 A075801 A243160 * A292370 A116943 A328389

Adjacent sequences:  A272691 A272692 A272693 * A272695 A272696 A272697

KEYWORD

sign

AUTHOR

N. J. A. Sloane, Jun 08 2016

STATUS

approved

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Last modified January 17 09:32 EST 2020. Contains 330949 sequences. (Running on oeis4.)