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A364536
Number of strict integer partitions of n where some part is a difference of two consecutive parts.
10
0, 0, 0, 1, 0, 0, 2, 1, 2, 2, 5, 4, 6, 6, 9, 11, 16, 17, 23, 25, 30, 38, 48, 55, 65, 78, 92, 106, 127, 146, 176, 205, 230, 277, 315, 366, 421, 483, 552, 640, 727, 829, 950, 1083, 1218, 1408, 1577, 1794, 2017, 2298, 2561, 2919, 3255, 3685, 4116, 4638, 5163
OFFSET
0,7
COMMENTS
In other words, strict partitions with parts not disjoint from first differences.
EXAMPLE
The a(3) = 1 through a(15) = 11 partitions (A = 10, B = 11, C = 12):
21 . . 42 421 431 63 532 542 84 742 743 A5
321 521 621 541 632 642 841 752 843
631 821 651 A21 761 942
721 5321 921 5431 842 C21
4321 5421 6421 B21 6432
6321 7321 6431 6531
6521 7431
7421 7521
8321 8421
9321
54321
MATHEMATICA
Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&Intersection[#, -Differences[#]]!={}&]], {n, 0, 30}]
PROG
(Python)
from collections import Counter
from sympy.utilities.iterables import partitions
def A364536(n): return sum(1 for s, p in map(lambda x: (x[0], tuple(sorted(Counter(x[1]).elements()))), filter(lambda p:max(p[1].values(), default=1)==1, partitions(n, size=True))) if not set(p).isdisjoint({p[i+1]-p[i] for i in range(s-1)})) # Chai Wah Wu, Sep 26 2023
CROSSREFS
For all differences of pairs we have A363226, non-strict A363225.
For all non-differences of pairs we have A364346, strict A364345.
The strict complement is counted by A364464, non-strict A363260.
For subsets of {1..n} we have A364466, complement A364463.
The non-strict case is A364467, ranks A364537.
A000041 counts integer partitions, strict A000009.
A008284 counts partitions by length, strict A008289.
A323092 counts double-free partitions, strict A120641.
A325325 counts partitions with distinct first-differences, strict A320347.
Sequence in context: A325110 A357888 A145862 * A058701 A004559 A214968
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jul 31 2023
STATUS
approved