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A249152 Exponent of 2 in the hyperfactorials: a(n) = A007814(A002109(n)). 4
0, 0, 2, 2, 10, 10, 16, 16, 40, 40, 50, 50, 74, 74, 88, 88, 152, 152, 170, 170, 210, 210, 232, 232, 304, 304, 330, 330, 386, 386, 416, 416, 576, 576, 610, 610, 682, 682, 720, 720, 840, 840, 882, 882, 970, 970, 1016, 1016, 1208, 1208, 1258, 1258, 1362, 1362, 1416, 1416, 1584, 1584, 1642, 1642 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

This is the function ord_2(D*_n) listed in the leftmost column of Table 7.1 in Lagarias & Mehta 2014 paper (on page 19).

LINKS

Table of n, a(n) for n=0..59.

Jeffrey C. Lagarias, Harsh Mehta, Products of binomial coefficients and unreduced Farey fractions, arXiv:1409.4145 [math.NT], 2014.

FORMULA

a(n) = 2 * A143157(floor(n/2)).

a(n) = A007814(A002109(n)).

a(n) = A174605(n) + A187059(n).

PROG

(Scheme, two alternative implementations)

(define (A249152 n) (A007814 (A002109 n)))

(define (A249152 n) (* 2 (A143157 (floor->exact (/ n 2)))))

CROSSREFS

Bisection: A249153.

Cf. A174605, A187059, A002109, A007814, A091512, A143157.

Sequence in context: A141610 A019241 A168295 * A216708 A032005 A147801

Adjacent sequences:  A249149 A249150 A249151 * A249153 A249154 A249155

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 25 2014

STATUS

approved

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Last modified June 19 00:55 EDT 2019. Contains 324217 sequences. (Running on oeis4.)