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A200792
Number of partitions of n such that the number of parts and the greatest part are not coprime.
2
0, 0, 1, 1, 3, 3, 7, 8, 12, 14, 24, 29, 43, 53, 72, 87, 119, 145, 196, 241, 314, 386, 505, 617, 786, 960, 1202, 1456, 1813, 2186, 2698, 3253, 3975, 4778, 5827, 6979, 8463, 10127, 12217, 14566, 17509, 20810, 24895, 29513, 35128, 41496, 49220, 57949, 68445
OFFSET
1,5
LINKS
EXAMPLE
a(5) = 3: [1,1,1,2], [1,1,3], [1,4].
a(6) = 3: [1,1,2,2], [1,2,3], [2,4].
a(7) = 7: [1,1,1,1,1,2], [1,2,2,2], [2,2,3], [1,3,3], [1,1,1,4], [3,4], [1,6].
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]; Table[a[n], {n, 1, 60}] (* Jean-François Alcover, Feb 06 2017, translated from Maple *)
CROSSREFS
Cf. A199887.
Sequence in context: A021886 A178238 A255333 * A218567 A161416 A241637
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Nov 22 2011
STATUS
approved