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A088488 a(n) = Sum_{k=1..8} floor(A254876(n,k)/A254876(n-1,k)), where A254876(n,k) = n! / (Product_{m=(n-floor((2n)/(3^k))) .. (n-floor((n)/(3^k)))} m). 6
8, 17, 22, 26, 40, 43, 49, 66, 65, 69, 87, 87, 68, 109, 108, 109, 137, 130, 130, 157, 153, 133, 180, 174, 171, 211, 196, 191, 227, 218, 186, 250, 240, 232, 280, 262, 253, 298, 285, 164, 319, 304, 292, 350, 327, 313, 367, 349, 292, 390, 371, 354, 426, 393, 375 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

A self-similar Cantor-type sequence with eight levels. [The original name of the sequence.]

This sequence resembles a Conway $10000-type chaotic sequence in its plot.

From Antti Karttunen, Feb 09 2015: (Start)

The above claim is dubious. The plots of this and A004001 do not resemble each other, at least for the first 10000 terms when using the plot-script of OEIS server.

The first three eights occur in positions 2, 3281, 9842.

(End)

LINKS

Antti Karttunen, Table of n, a(n) for n = 2..10000

FORMULA

a(n) = Sum_{k=1..8} floor(A254876(n,k)/A254876(n-1,k)), where A254876(n,k) = n! / (Product_{m=(n-floor((2n)/(3^k))) .. (n-floor((n)/(3^k)))} m).

MATHEMATICA

p[n_, k_]=n!/Product[i, {i, n-Floor[2*n/3^k], n-Floor[n/3^k]}] digits=200 f[n_]=Sum[Floor[p[n, k]/p[n-1, k]], {k, 1, 8}] at=Table[f[n], {n, 2, digits}] (* fractal plot*) ListPlot[at, PlotJoined->True, PlotRange->All]

PROG

(PARI)

A088488(n) = sum(k=1, 8, (A254876bi(n, k)\A254876bi(n-1, k)));

A254876bi(n, k) = n! / prod(i=(n-((2*n)\(3^k))), (n-(n\(3^k))), i);

for(n=2, 10000, write("b088488.txt", n, " ", A088488(n)));

(Scheme)

(define (A088488 n) (add (lambda (k) (floor->exact (/ (A254876bi n k) (A254876bi (- n 1) k)))) 1 8))

;; The following function implements sum_{i=lowlim..uplim} intfun(i)

(define (add intfun lowlim uplim) (let sumloop ((i lowlim) (res 0)) (cond ((> i uplim) res) (else (sumloop (1+ i) (+ res (intfun i)))))))

CROSSREFS

Cf. A000142, A004001, A088487, A254876.

Sequence in context: A271626 A023700 A026231 * A031458 A044991 A063594

Adjacent sequences:  A088485 A088486 A088487 * A088489 A088490 A088491

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Nov 09 2003

EXTENSIONS

Edited by Antti Karttunen, Feb 09 2015

STATUS

approved

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Last modified July 21 06:55 EDT 2019. Contains 325192 sequences. (Running on oeis4.)