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A276575 After a(0)=0, the first differences of A276573. 6
0, 3, 3, 2, 3, 4, 1, 2, 3, 3, 3, 3, 2, 3, 3, 2, 3, 2, 3, 3, 2, 3, 3, 4, 1, 3, 3, 2, 3, 3, 2, 3, 2, 3, 2, 3, 3, 3, 3, 3, 3, 4, 3, 2, 3, 3, 3, 2, 3, 3, 2, 3, 4, 1, 3, 2, 3, 3, 3, 2, 2, 3, 3, 3, 2, 3, 3, 4, 3, 3, 3, 3, 3, 2, 3, 4, 3, 3, 3, 3, 2, 3, 3, 4, 2, 3, 4, 3, 2, 3, 3, 4, 1, 3, 2, 3, 3, 3, 2, 3, 2, 3, 3, 3, 2, 3, 3, 2, 2, 3, 3, 2, 3, 3, 3, 3, 2, 3, 3, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..10028

Burkard Polster, Root 2 and the deadly Marching Squares, Mathologer video (2015)

FORMULA

a(n) = A002828(A276573(n)).

a(0) = 0; for n >= 1, a(n) = A276573(n) - A276573(n-1).

Other identities.

For all n >= 1, a(A260731(A132592(n))) = a(A260733(A001541(n))) = 2. [This is implied by the fact observed in the Polster video. Of course 2's occur at other points too.]

PROG

(Scheme, two alternatives)

(define (A276575 n) (A002828 (A276573 n)))

(define (A276575 n) (if (zero? n) n (- (A276573 n) (A276573 (- n 1)))))

CROSSREFS

Cf. A001541, A002828, A132592, A260731, A260733, A276573.

Sequence in context: A031352 A245885 A188834 * A244540 A276585 A057853

Adjacent sequences:  A276572 A276573 A276574 * A276576 A276577 A276578

KEYWORD

nonn

AUTHOR

Antti Karttunen, Sep 07 2016

STATUS

approved

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Last modified February 18 04:48 EST 2020. Contains 332011 sequences. (Running on oeis4.)