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A303362 Number of strict integer partitions of n with pairwise indivisible parts. 51
1, 1, 1, 1, 2, 1, 3, 2, 3, 4, 5, 4, 6, 7, 7, 9, 11, 12, 13, 15, 17, 20, 23, 25, 27, 32, 35, 40, 45, 50, 55, 58, 67, 78, 84, 95, 101, 113, 124, 137, 153, 169, 180, 198, 219, 242, 268, 291, 319, 342, 374, 412, 450, 492, 535, 573, 632, 685, 746, 813, 868, 944 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..250

EXAMPLE

The a(14) = 7 strict integer partitions are (14), (11,3), (10,4), (9,5), (8,6), (7,5,2), (7,4,3).

MATHEMATICA

Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&Select[Tuples[#, 2], UnsameQ@@#&&Divisible@@#&]==={}&]], {n, 60}]

PROG

(PARI)

lista(nn)={local(Cache=Map());

  my(excl=vector(nn, n, sumdiv(n, d, 2^(n-d))));

  my(a(n, m=n, b=0)=

     if(n==0, 1,

        while(m>n || bittest(b, 0), m--; b>>=1);

        my(hk=[n, m, b], z);

        if(!mapisdefined(Cache, hk, &z),

          z = if(m, self()(n, m-1, b>>1) + self()(n-m, m, bitor(b, excl[m])), 0);

          mapput(Cache, hk, z)); z));

   for(n=1, nn, print1(a(n), ", "))

} \\ Andrew Howroyd, Nov 02 2019

CROSSREFS

Cf. A000009, A000837, A003238, A006126, A051424, A259936, A275307, A281116, A285572, A285573, A290103, A293606, A293993, A303364.

Sequence in context: A285779 A319320 A305194 * A183163 A122545 A072515

Adjacent sequences:  A303359 A303360 A303361 * A303363 A303364 A303365

KEYWORD

nonn

AUTHOR

Gus Wiseman, Apr 22 2018

STATUS

approved

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Last modified August 6 16:05 EDT 2020. Contains 336255 sequences. (Running on oeis4.)