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Revision History for A191278

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Showing all changes.
Count of Mosaic numbers that equal n.
(history; published version)
#6 by R. J. Mathar at Sat May 27 12:53:40 EDT 2017
STATUS

editing

approved

#5 by R. J. Mathar at Sat May 27 12:53:22 EDT 2017
LINKS

R. J. Mathar, <a href="/A191278/b191278.txt">Table of n, a(n) for n = 1..1000</a>

MAPLE

A073093 := proc(n) local f, beta, j ; f := ifactors(n)[2] ; beta := 1 ; for j from 1 to nops(f) do beta := beta + op(2, op(j, f)) ; end do: beta ; end proc:

A := proc(n) local f, beta, a, j ; f := ifactors(n)[2] ; beta := A073093(n) ; a := 1/beta ; for j in ifactors(n)[2] do a := a*binomial(beta, op(2, j) ) ; end do: a ; end proc:

seq(A(n), n=1..90) ;

A191278 := proc(n)

local f, beta, a, j ;

f := ifactors(n)[2] ;

beta := A073093(n) ;

a := 1/beta ;

for j in ifactors(n)[2] do

a := a*binomial(beta, op(2, j) ) ;

end do:

a ;

end proc:

STATUS

approved

editing

#4 by Russ Cox at Fri Mar 30 17:40:29 EDT 2012
AUTHOR

_R. J. Mathar (mathar(AT)strw.leidenuniv.nl), _, May 29 2011

Discussion
Fri Mar 30
17:40
OEIS Server: https://oeis.org/edit/global/190
#3 by N. J. A. Sloane at Sun May 29 14:11:12 EDT 2011
STATUS

proposed

approved

#2 by R. J. Mathar at Sun May 29 12:09:11 EDT 2011
NAME

allocated for R. J. Mathar

Count of Mosaic numbers that equal n.

DATA

1, 1, 1, 1, 1, 3, 1, 1, 1, 3, 1, 6, 1, 3, 3, 1, 1, 6, 1, 6, 3, 3, 1, 10, 1, 3, 1, 6, 1, 16, 1, 1, 3, 3, 3, 20, 1, 3, 3, 10, 1, 16, 1, 6, 6, 3, 1, 15, 1, 6, 3, 6, 1, 10, 3, 10, 3, 3, 1, 50, 1, 3, 6, 1, 3, 16, 1, 6, 3, 16, 1, 50, 1, 3, 6, 6, 3, 16, 1, 15, 1, 3, 1, 50, 3, 3, 3, 10, 1, 50

OFFSET

1,6

COMMENTS

The number of solutions x to A000026(x)=n.

FORMULA

Let n=product_j p_j^e(j) be the prime factorization of n and beta=A073093(n). Then a(n)*beta = product_j binomial(beta,e(j)). [Gordon-Robertson in A000026, Theorem 1]

MAPLE

A073093 := proc(n) local f, beta, j ; f := ifactors(n)[2] ; beta := 1 ; for j from 1 to nops(f) do beta := beta + op(2, op(j, f)) ; end do: beta ; end proc:

A := proc(n) local f, beta, a, j ; f := ifactors(n)[2] ; beta := A073093(n) ; a := 1/beta ; for j in ifactors(n)[2] do a := a*binomial(beta, op(2, j) ) ; end do: a ; end proc:

seq(A(n), n=1..90) ;

KEYWORD

allocated

nonn,easy

AUTHOR

R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 29 2011

STATUS

approved

proposed

#1 by R. J. Mathar at Sun May 29 12:09:11 EDT 2011
NAME

allocated for R. J. Mathar

KEYWORD

allocated

STATUS

approved