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A245214 Numbers n such that A245212(n) < 0. 4
144, 192, 216, 240, 288, 336, 360, 384, 432, 480, 504, 540, 576, 600, 648, 672, 720, 768, 792, 840, 864, 900, 936, 960, 1008, 1056, 1080, 1152, 1200, 1248, 1260, 1296, 1320, 1344, 1440, 1512, 1536, 1560, 1584, 1620, 1632, 1680, 1728, 1800, 1824, 1848, 1872, 1920, 1944, 1980, 2016, 2040, 2100, 2112, 2160, 2240 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If d are divisors of n then values of sequence A245212(n) are by bending moments in point 0 of static forces of sizes tau(d) operating in places d on the cantilever as the nonnegative number axis of length n with bracket in point 0 by the schema: A245212(n) = (n * tau(n)) - Sum_((d<n) | n) (d * tau(d)).

Numbers n such that A038040(n) = n * tau(n) < A245211(n) = Sum_((d<n) | n) (d * tau(d)).

LINKS

Jens Kruse Andersen, Table of n, a(n) for n = 1..10000

EXAMPLE

Number 144 is in sequence because 144 * tau(144) = 2160  < Sum_((d<144) | 144) (d * tau(d)) = 2226.

PROG

(MAGMA) [n: n in [1..100000] | (2*(n*(#[d: d in Divisors(n)]))-(&+[d*#([e: e in Divisors(d)]): d in Divisors(n)])) lt 0]

(PARI) isok(n) = (n*numdiv(n) - sumdiv(n, d, (d<n)*d*numdiv(d))) < 0; \\ Michel Marcus, Aug 06 2014

CROSSREFS

Cf. A000005, A038040, A245211, A245212, A245213.

Sequence in context: A064021 A156316 A323614 * A257412 A165076 A165078

Adjacent sequences:  A245211 A245212 A245213 * A245215 A245216 A245217

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jul 23 2014

STATUS

approved

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Last modified January 29 01:54 EST 2020. Contains 331328 sequences. (Running on oeis4.)