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A160357 Sign of first differences of Recamán's sequence A005132. 9
1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = sign(A005132(n)-A005132(n-1)) = sign(A160356(n)) = (-1)^A160351(n) = -(-1)^A076213(n-1).

a(n) = (A005132(n)-A005132(n-1))/n. - N. J. A. Sloane, Jul 15 2011

A160357 = chi_A057165 - chi_A057166, where chi_A denotes the characteristic function of (the set of values of) A.

MAPLE

A160357 := proc(n)

        sign( A005132(n)-A005132(n-1)) ;

end proc: # R. J. Mathar, Apr 01 2012

CROSSREFS

Cf. A005132, A119632.

Sequence in context: A121238 A131554 A153881 * A057077 A070748 A154990

Adjacent sequences:  A160354 A160355 A160356 * A160358 A160359 A160360

KEYWORD

sign

AUTHOR

M. F. Hasler, Jun 03 2009

STATUS

approved

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Last modified November 20 14:53 EST 2018. Contains 317402 sequences. (Running on oeis4.)