login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A290253 Triangle read by rows. Row n consists of the parts, ordered nonincreasingly, of the integer partition having viabin number n. 7
0, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 3, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 3, 1, 2, 2, 2, 3, 2, 3, 3, 4, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 3, 1, 1, 2, 2, 2, 1, 3, 2, 1, 3, 3, 1, 4, 1, 2, 2, 2, 2, 3, 2, 2, 3, 3, 2, 4, 2, 3, 3, 3, 4, 3, 4, 4, 5, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 3, 1, 1, 1, 2, 2, 2, 1, 1, 3, 2, 1, 1, 3, 3, 1, 1, 4, 1, 1, 2, 2, 2, 2, 1, 3, 2, 2, 1, 3, 3, 2, 1, 4, 2, 1, 3, 3, 3, 1, 4, 3, 1, 4, 4, 1, 5, 1, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 3, 2, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

The viabin number of an integer partition is defined in the following way. Consider the southeast border of the Ferrers board of the integer partition and consider the binary number obtained by replacing each east step with 1 and each north step, except the last one, with 0. The corresponding decimal form is, by definition, the viabin number of the given integer partition. "Viabin" is coined from "via binary". For example, consider the integer partition [2,2,2,1]. The southeast border of its Ferrers board yields 10100, leading to the viabin number 20.

Number of entries in row n is A290251(n).

In the Maple program the command vitopart(n) yields the integer partition having viabin number n.

LINKS

Alois P. Heinz, Rows n = 0..4095, flattened

EXAMPLE

Row 25 is 3,2,2. Indeed, the binary form of 25 is 11001. Consequently, the southeast border of the Ferrers board of the associated partition is EENNEN, where E and N are the steps [1,0] and [0,1], respectively. This leads to the partition [3,2,2].

Triangle begins:

0,

1;

1,1;

2;

1,1,1;

2,1;

2,2;

3;

MAPLE

# (due to W. Edwin Clark)

vitopart := proc (n) local L, i, j, N, p, t; N := 2*n; L := ListTools:-Reverse(convert(N, base, 2)); j := 0; for i to nops(L) do if L[i] = 0 then j := j+1; p[j] := numboccur(L[1 .. i], 1) end if end do; sort([seq(p[t], t = 1 .. j)], `>=`) end proc:

# second Maple program:

T:= proc(n) local m; m:= n; [0]; while m>0 do `if`(1=

      irem(m, 2, 'm'), map(x-> x+1, %), [%[], 0]) od: %[]

    end:

seq(T(n), n=0..50);  # Alois P. Heinz, Aug 23 2017

CROSSREFS

Row sums give A161511.

Row lengths give A008687(n+1).

Cf. A253563, A290251.

Sequence in context: A138474 A058761 A050119 * A097637 A161094 A241597

Adjacent sequences:  A290250 A290251 A290252 * A290254 A290255 A290256

KEYWORD

nonn,tabf

AUTHOR

Emeric Deutsch, Aug 23 2017

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 25 20:58 EST 2018. Contains 299656 sequences. (Running on oeis4.)