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A091860 a(1)=1, a(n)=sum(i=1,n-1,b(i)) where b(i)=0 if a(i) and a(n-i) are both even, b(i)=1 otherwise. 0
1, 1, 2, 3, 4, 4, 6, 5, 6, 6, 8, 6, 8, 8, 8, 7, 8, 8, 10, 8, 10, 10, 10, 8, 10, 10, 10, 10, 10, 10, 10, 9, 10, 10, 12, 10, 12, 12, 12, 10, 12, 12, 12, 12, 12, 12, 12, 10, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 11, 12, 12, 14, 12, 14, 14, 14, 12, 14, 14, 14, 14, 14 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..77.

FORMULA

n>1 a(2n)=a(n)+2; if n is a power of 2, a(2n+1)=1+a(2n); if n is the sum of 2 distinct power of 2, a(2n+1)=2+a(2n); a(2n+1)=a(2n) otherwise

PROG

(PARI) an[1]=1; for(n=2, 100, an[n]=sum(i=1, n-1, max(a(i)%2, a(n-i)%2)))

CROSSREFS

Cf. A018900, A072823.

Sequence in context: A178031 A008328 A298933 * A333995 A301764 A181833

Adjacent sequences:  A091857 A091858 A091859 * A091861 A091862 A091863

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Mar 16 2004

STATUS

approved

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Last modified November 24 18:11 EST 2020. Contains 338616 sequences. (Running on oeis4.)