[go: up one dir, main page]

login
A114638
Number of partitions of n such that number of parts is equal to the sum of parts counted without multiplicities.
21
1, 1, 0, 0, 2, 1, 1, 0, 2, 2, 3, 5, 5, 6, 9, 7, 8, 14, 12, 16, 21, 28, 32, 43, 47, 61, 68, 84, 89, 109, 126, 140, 170, 198, 227, 261, 323, 362, 427, 501, 581, 658, 794, 880, 1036, 1175, 1355, 1526, 1776, 1985, 2281, 2588, 2943, 3312, 3799, 4271, 4852, 5497
OFFSET
0,5
COMMENTS
The Heinz numbers of these integer partitions are given by A324570. - Gus Wiseman, Mar 09 2019
LINKS
EXAMPLE
a(10) = 3 because we have [5,1,1,1,1,1], [3,3,3,1] and [3,2,2,1,1,1].
From Gus Wiseman, Mar 09 2019: (Start)
The a(1) = 1 through a(12) = 5 integer partitions (empty columns not shown):
1 22 221 3111 3311 333 3331 32222 33222
211 41111 321111 322111 44111 322221
511111 322211 332211
332111 4221111
4211111 6111111
(End)
MAPLE
a:=proc(n) local P, c, j, S: with(combinat): P:=partition(n): c:=0: for j from 1 to nops(P) do S:=convert(P[j], set): if nops(P[j])=sum(S[i], i=1..nops(S)) then c:=c+1 else c:=c fi: c: od: end: seq(a(n), n=0..35); # Emeric Deutsch, Mar 01 2006
MATHEMATICA
a[n_] := Module[{P, c, j, S}, P = IntegerPartitions[n]; c = 0; For[j = 1, j <= Length[P], j++, S = Union[P[[j]]]; If[Length[P[[j]]] == Total[S], c++] ]; c];
Table[a[n], {n, 0, 60}] (* Jean-François Alcover, May 07 2018, after Emeric Deutsch *)
PROG
(PARI) apply( A114638(n, s=0)={forpart(p=n, #p==vecsum(Set(p))&&s++); s}, [0..50]) \\ M. F. Hasler, Oct 27 2019
CROSSREFS
Cf. A003114, A006141, A039900, A047993, A064174, A066328, A243149 (the same for compositions).
Cf. A116861 (number of partitions of n having a given sum of distinct parts).
Sequence in context: A331410 A336928 A366388 * A123340 A360455 A267486
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, Feb 18 2006
EXTENSIONS
More terms from Emeric Deutsch, Mar 01 2006
STATUS
approved