A276575 - OEIS

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A276575

After a(0)=0, the first differences of A276573.

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: A374406 A245885 A188834 * A244540 A337682 A276585

Adjacent sequences: A276572 A276573 A276574 * A276576 A276577 A276578

KEYWORD

nonn

AUTHOR

Antti Karttunen, Sep 07 2016

STATUS

approved