cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A320348 Number of partition into distinct parts (a_1, a_2, ... , a_m) (a_1 > a_2 > ... > a_m and Sum_{k=1..m} a_k = n) such that a1 - a2, a2 - a_3, ... , a_{m-1} - a_m, a_m are different.

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%I A320348 #25 Feb 23 2021 10:08:15
%S A320348 1,1,1,2,3,2,4,4,4,6,9,7,13,12,13,16,22,17,28,28,31,36,50,45,63,62,74,
%T A320348 78,102,92,123,123,146,148,191,181,228,233,280,283,348,350,420,437,
%U A320348 518,523,616,641,727,774,884,911,1038,1102,1240,1292,1463,1530,1715,1861,2002
%N A320348 Number of partition into distinct parts (a_1, a_2, ... , a_m) (a_1 > a_2 > ... > a_m and Sum_{k=1..m} a_k = n) such that a1 - a2, a2 - a_3, ... , a_{m-1} - a_m, a_m are different.
%C A320348 Also the number of integer partitions of n whose parts cover an initial interval of positive integers with distinct multiplicities. Also the number of integer partitions of n whose multiplicities cover an initial interval of positive integers and are distinct (see A048767 for a bijection). - _Gus Wiseman_, May 04 2019
%H A320348 Fausto A. C. Cariboni, <a href="/A320348/b320348.txt">Table of n, a(n) for n = 1..500</a> (terms 1..100 from Seiichi Manyama)
%H A320348 Gus Wiseman, <a href="/A325325/a325325.txt">Sequences counting and ranking integer partitions by the differences of their successive parts.</a>
%e A320348 n = 9
%e A320348 [9]        *********  a_1 = 9.
%e A320348            ooooooooo
%e A320348 ------------------------------------
%e A320348 [8, 1]             *        a_2 = 1.
%e A320348             *******o  a_1 - a_2 = 7.
%e A320348             oooooooo
%e A320348 ------------------------------------
%e A320348 [7, 2]            **        a_2 = 2.
%e A320348              *****oo  a_1 - a_2 = 5.
%e A320348              ooooooo
%e A320348 ------------------------------------
%e A320348 [5, 4]          ****        a_2 = 4.
%e A320348                *oooo  a_1 - a_2 = 1.
%e A320348                ooooo
%e A320348 ------------------------------------
%e A320348 a(9) = 4.
%e A320348 From _Gus Wiseman_, May 04 2019: (Start)
%e A320348 The a(1) = 1 through a(11) = 9 strict partitions with distinct differences (where the last part is taken to be 0) are the following (A = 10, B = 11). The Heinz numbers of these partitions are given by A325388.
%e A320348   (1)  (2)  (3)  (4)   (5)   (6)   (7)   (8)   (9)   (A)    (B)
%e A320348                  (31)  (32)  (51)  (43)  (53)  (54)  (64)   (65)
%e A320348                        (41)        (52)  (62)  (72)  (73)   (74)
%e A320348                                    (61)  (71)  (81)  (82)   (83)
%e A320348                                                      (91)   (92)
%e A320348                                                      (631)  (A1)
%e A320348                                                             (632)
%e A320348                                                             (641)
%e A320348                                                             (731)
%e A320348 The a(1) = 1 through a(10) = 6 partitions covering an initial interval of positive integers with distinct multiplicities are the following. The Heinz numbers of these partitions are given by A325326.
%e A320348   1  11  111  211   221    21111   2221     22211     22221      222211
%e A320348               1111  2111   111111  22111    221111    2211111    322111
%e A320348                     11111          211111   2111111   21111111   2221111
%e A320348                                    1111111  11111111  111111111  22111111
%e A320348                                                                  211111111
%e A320348                                                                  1111111111
%e A320348 The a(1) = 1 through a(10) = 6 partitions whose multiplicities cover an initial interval of positive integers and are distinct are the following (A = 10). The Heinz numbers of these partitions are given by A325337.
%e A320348   (1)  (2)  (3)  (4)    (5)    (6)    (7)    (8)    (9)    (A)
%e A320348                  (211)  (221)  (411)  (322)  (332)  (441)  (433)
%e A320348                         (311)         (331)  (422)  (522)  (442)
%e A320348                                       (511)  (611)  (711)  (622)
%e A320348                                                            (811)
%e A320348                                                            (322111)
%e A320348 (End)
%t A320348 Table[Length[Select[IntegerPartitions[n],UnsameQ@@#&&UnsameQ@@Differences[Append[#,0]]&]],{n,30}] (* _Gus Wiseman_, May 04 2019 *)
%Y A320348 Cf. A000009, A320347.
%Y A320348 Cf. A007294, A007862, A048767, A098859, A179269, A320509, A320510, A325324, A325325, A325349, A325367, A325404, A325468.
%K A320348 nonn
%O A320348 1,4
%A A320348 _Seiichi Manyama_, Oct 11 2018