The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A101638 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A101638

Number of distinct 4-almost primes A014613 which are factors of n.
(history; published version)

#17 by Bruno Berselli at Thu Oct 05 11:34:36 EDT 2017

STATUS

proposed

approved

#16 by Michel Marcus at Thu Oct 05 11:29:34 EDT 2017

STATUS

editing

proposed

#15 by Michel Marcus at Thu Oct 05 11:29:29 EDT 2017

REFERENCES

Bender, E. A. and Goldman, J. R. "On the Applications of Moebius Inversion in Combinatorial Analysis." Amer. Math. Monthly 82, 789-803, 1975.

LINKS

E. A. Bender and J. R. Goldman, <a href="https://www.maa.org/sites/default/files/pdf/upload_library/22/Ford/BenderGoldman.pdf">On the Applications of Moebius Inversion in Combinatorial Analysis</a>, Amer. Math. Monthly 82, 789-803, 1975.

STATUS

approved

editing

#14 by N. J. A. Sloane at Mon May 08 00:03:39 EDT 2017

STATUS

editing

approved

#13 by N. J. A. Sloane at Mon May 08 00:03:17 EDT 2017

LINKS

M. Bernstein and N. J. A. Sloane, <a href="/A003633/a003633_1.pdf">Some canonical sequences of integers</a>, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures]

STATUS

approved

editing

#12 by N. J. A. Sloane at Sun May 07 16:36:07 EDT 2017

LINKS

M. Bernstein and N. J. A. Sloane, <a href="http://arXiv.org/abs/math.CO/0205301">Some canonical sequences of integers</a>, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to arXiv version]

Discussion

Sun May 07

16:36

OEIS Server: https://oeis.org/edit/global/2649

#11 by Charles R Greathouse IV at Mon Sep 14 11:15:07 EDT 2015

STATUS

editing

approved

#10 by Charles R Greathouse IV at Mon Sep 14 11:14:59 EDT 2015

LINKS

Charles R Greathouse IV, <a href="/A101638/b101638.txt">Table of n, a(n) for n = 1..10000</a>

PROG

(PARI) a(n)=my(f=factor(n)[, 2], v=apply(k->sum(i=1, #f, f[i]>k), [0..3])); v[4] + v[3]*(v[1]-1) + binomial(v[2], 2) + v[2]*binomial(v[1]-1, 2) + binomial(v[1], 4) \\ Charles R Greathouse IV, Sep 14 2015

STATUS

approved

editing

#9 by Charles R Greathouse IV at Thu Apr 26 21:31:12 EDT 2012

STATUS

editing

approved

#8 by Charles R Greathouse IV at Thu Apr 26 21:31:07 EDT 2012

NAME

a(n) = the number Number of distinct 4-almost primes A014613 which are factors of n.

STATUS

approved

editing