login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A270774 a(n) = (A005706(n) - A194459(n))/5. 0
0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 3, 3, 3, 3, 3, 6, 6, 6, 6, 6, 10, 10, 10, 10, 10, 16, 17, 18, 19, 20, 23, 24, 25, 26, 27, 32, 33, 34, 35, 36, 43, 44, 45, 46, 47, 56, 57, 58, 59, 60, 73, 76, 79, 82, 85, 91, 94, 97, 100, 103, 112, 115, 118, 121 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,11

COMMENTS

A combinatorial interpretation is given in the Edgar link.

LINKS

Table of n, a(n) for n=0..63.

G. E. Andrews, A. S. Fraenkel, and J. A. Sellers, Characterizing the number of m-ary partitions modulo m, The American Mathematical Monthly, Vol. 122, No. 9 (November 2015), pp. 880-885.

G. E. Andrews, A. S. Fraenkel, and J. A. Sellers, Characterizing the number of m-ary partitions modulo m.

Tom Edgar, The distribution of the number of parts of m-ary partitions modulo m., arXiv:1603.00085 [math.CO], 2016.

FORMULA

Let b(0) = 1 and b(n) = b(n-1) + b(floor(n/5)) and let c(n) = Product_{i=0..k}(n_i+1) where n = Sum_{i=0..k}n_i*5^i is the base 5 representation of n. Then a(n) = (1/5)*(b(n) - c(n)).

MATHEMATICA

b[0] = 1; b[n_] := b[n] = b[n-1] + b[Floor[n/5]];

c[n_] := If[OddQ[n], 2 Count[Table[Binomial[n, k], {k, 0, (n-1)/2}], c_ /; !Divisible[c, 5]], 2 Count[Table[Binomial[n, k], {k, 0, (n-2)/2}], c_ /; !Divisible[c, 5]] + Boole[!Divisible[Binomial[n, n/2], 5]]];

a[n_] := (b[n] - c[n])/5;

Table[a[n], {n, 0, 63}] (* Jean-Fran├žois Alcover, Feb 15 2019 *)

PROG

(Sage)

def b(n):

    A=[1]

    for i in [1..n]:

        A.append(A[i-1] + A[i//5])

    return A[n]

print([(b(n)-prod(x+1 for x in n.digits(5)))/5 for n in [0..63]])

CROSSREFS

Cf. A005706, A194459, A268127, A268128, A268443.

Sequence in context: A105591 A130497 A178154 * A263144 A126715 A158805

Adjacent sequences:  A270771 A270772 A270773 * A270775 A270776 A270777

KEYWORD

nonn

AUTHOR

Tom Edgar, Mar 22 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 17 01:26 EDT 2021. Contains 343051 sequences. (Running on oeis4.)