A247935 Number of integer partitions of n whose distinct parts have no binary carries.

1, 1, 2, 3, 4, 5, 8, 10, 11, 14, 18, 21, 26, 30, 38, 49, 47, 55, 66, 74, 84, 96, 110, 126, 134, 151, 171, 195, 209, 235, 272, 318, 307, 349, 377, 422, 448, 491, 534, 595, 617, 674, 734, 801, 841, 925, 998, 1098, 1118, 1219, 1299, 1418, 1476, 1591, 1711, 1865

Offset: 0

Author

David S. Newman, Sep 26 2014

Keywords

• nonn

Comments

From Gus Wiseman, Mar 31 2019: (Start)

A binary carry of two positive integers is an overlap of the positions of 1's in their reversed binary expansion. For example, the reversed binary expansions of 2, 5, and 8 are

{0,1}

{1,0,1}

{0,0,0,1}

and since there are no columns with more than one 1, the partition (8,5,2) is counted under a(15). The Heinz numbers of these partitions are given by A325097.

(End)

Examples

			From _Gus Wiseman_, Mar 30 2019: (Start)
The a(1) = 1 through a(8) = 11 partitions:
  (1)  (2)   (3)    (4)     (5)      (6)       (7)        (8)
       (11)  (21)   (22)    (41)     (33)      (43)       (44)
             (111)  (211)   (221)    (42)      (52)       (422)
                    (1111)  (2111)   (222)     (61)       (611)
                            (11111)  (411)     (421)      (2222)
                                     (2211)    (2221)     (4211)
                                     (21111)   (4111)     (22211)
                                     (111111)  (22111)    (41111)
                                               (211111)   (221111)
                                               (1111111)  (2111111)
                                                          (11111111)
(End)
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A000110, A000120, A050315, A070939, A080572, A248605, A267610.

Cf. A325095, A325096, A325097, A325098, A325102, A325103, A325109.

Programs

Maple

with(Bits):
b:= proc(n, i, t) option remember; `if`(n=0, 1, `if`(i<1, 0,
      b(n, i-1, t) +`if`(i>n or And(t, i)>0, 0,
      add(b(n-i*j, i-1, Or(t, i)), j=1..n/i))))
    end:
a:= n-> b(n$2, 0):
seq(a(n), n=0..80);  # Alois P. Heinz, Dec 28 2014

Mathematica

binpos[n_]:=Join@@Position[Reverse[IntegerDigits[n,2]],1];
stableQ[u_,Q_]:=!Apply[Or,Outer[#1=!=#2&&Q[#1,#2]&,u,u,1],{0,1}];
Table[Length[Select[IntegerPartitions[n],stableQ[#,Intersection[binpos[#1],binpos[#2]]!={}&]&]],{n,0,20}] (* Gus Wiseman, Mar 30 2019 *)
b[n_, i_, t_] := b[n, i, t] = If[n == 0, 1, If[i < 1, 0, b[n, i - 1, t] + If[i > n || BitAnd[t, i] > 0, 0, Sum[b[n - i*j, i - 1, BitOr[t, i]], {j, 1, n/i}]]]];
a[n_] := b[n, n, 0];
a /@ Range[0, 80] (* Jean-François Alcover, May 23 2021, after Alois P. Heinz *)

Extensions

More terms from Alois P. Heinz, Oct 15 2014

Name edited by Gus Wiseman, Mar 31 2019