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A200750 Number of partitions of n such that the number of parts and the greatest part are coprime. 24
1, 2, 2, 4, 4, 8, 8, 14, 18, 28, 32, 48, 58, 82, 104, 144, 178, 240, 294, 386, 478, 616, 750, 958, 1172, 1476, 1808, 2262, 2752, 3418, 4144, 5096, 6168, 7532, 9056, 10998, 13174, 15888, 18968, 22772, 27074, 32364, 38366, 45662, 54006, 64062, 75534, 89324 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..500

EXAMPLE

a(5) = 4: [1,1,1,1,1], [1,2,2], [2,3], [5].

a(6) = 8: [1,1,1,1,1,1], [1,1,1,1,2], [2,2,2], [1,1,1,3], [3,3], [1,1,4], [1,5], [6].

MAPLE

b:= proc(n, j, t) option remember;

      add(b(n-i, i, t+1), i=j..iquo(n, 2))+`if`(igcd(t, n)=1, 1, 0)

    end:

a:= n-> b(n, 1, 1):

seq(a(n), n=1..60);

MATHEMATICA

b[n_, j_, t_] := b[n, j, t] = Sum[b[n-i, i, t+1], {i, j, Quotient[n, 2]}] + If[GCD[t, n] == 1, 1, 0];

a[n_] := b[n, 1, 1];

Array[a, 60] (* Jean-Fran├žois Alcover, Dec 05 2020, after Alois P. Heinz *)

CROSSREFS

Cf. A199886.

Sequence in context: A205478 A262966 A034397 * A344607 A325722 A279818

Adjacent sequences:  A200747 A200748 A200749 * A200751 A200752 A200753

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Nov 21 2011

STATUS

approved

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Last modified May 26 09:53 EDT 2022. Contains 354086 sequences. (Running on oeis4.)