A325769
Number of integer partitions of n whose distinct consecutive subsequences have different sums.
Original entry on oeis.org
1, 1, 2, 3, 4, 6, 7, 11, 12, 17, 19, 29, 28, 41, 42, 62, 61, 88, 87, 123, 121, 168, 164, 234, 225, 306, 306, 411, 401, 527, 533, 700, 689, 894, 885, 1163, 1150, 1452, 1469, 1866, 1835, 2333, 2346, 2913, 2913, 3638, 3619, 4511, 4537, 5497, 5576, 6859, 6827, 8263
Offset: 0
The a(1) = 1 through a(8) = 12 partitions:
(1) (2) (3) (4) (5) (6) (7) (8)
(11) (21) (22) (32) (33) (43) (44)
(111) (31) (41) (42) (52) (53)
(1111) (221) (51) (61) (62)
(311) (222) (322) (71)
(11111) (411) (331) (332)
(111111) (421) (521)
(511) (611)
(2221) (2222)
(4111) (3311)
(1111111) (5111)
(11111111)
-
Table[Length[Select[IntegerPartitions[n],UnsameQ@@Total/@Union[ReplaceList[#,{_,s__,_}:>{s}]]&]],{n,0,30}]
A325685
Number of compositions of n whose distinct consecutive subsequences have different sums, and such that these sums cover an initial interval of positive integers.
Original entry on oeis.org
1, 1, 1, 3, 1, 5, 3, 5, 3, 9, 1, 9, 5, 7, 5, 11, 1, 13, 5, 9, 5, 13, 3, 13, 7, 9, 5, 17, 1, 17, 5, 9, 9, 15, 5, 15, 5, 13, 5, 21, 1, 17, 9, 9, 9, 17, 3, 21, 7, 13, 5, 17, 5, 21, 9, 13, 5, 21, 1, 21, 9, 11, 13, 19, 5, 17, 5, 17, 5, 29, 1, 21, 9, 9, 13, 17, 5, 25, 7, 17, 7
Offset: 0
The distinct consecutive subsequences of (3,4,1,1) together with their sums are:
1: {1}
2: {1,1}
3: {3}
4: {4}
5: {4,1}
6: {4,1,1}
7: {3,4}
8: {3,4,1}
9: {3,4,1,1}
Because the sums are all different and cover {1...9}, it follows that (3,4,1,1) is counted under a(9).
The a(1) = 1 through a(9) = 9 compositions:
1 11 12 1111 113 132 1114 1133 1143
21 122 231 1222 3311 1332
111 221 111111 2221 11111111 2331
311 4111 3411
11111 1111111 11115
12222
22221
51111
111111111
-
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],Sort[Total/@Union[ReplaceList[#,{_,s__,_}:>{s}]]]==Range[n]&]],{n,0,15}]
A325684
Number of minimal complete rulers of length n.
Original entry on oeis.org
1, 1, 1, 2, 3, 4, 5, 12, 12, 24, 40, 46, 92, 133, 192, 308, 546, 710, 1108, 1754, 2726, 3878, 5928, 9260, 14238, 20502, 30812, 48378, 72232, 105744, 160308, 241592, 362348, 540362, 797750, 1183984, 1786714
Offset: 0
The a(1) = 1 through a(7) = 12 rulers:
{0,1} {0,1,2} {0,1,3} {0,1,2,4} {0,1,2,5} {0,1,4,6} {0,1,2,3,7}
{0,2,3} {0,1,3,4} {0,1,3,5} {0,2,5,6} {0,1,2,4,7}
{0,2,3,4} {0,2,4,5} {0,1,2,3,6} {0,1,2,5,7}
{0,3,4,5} {0,1,3,5,6} {0,1,3,5,7}
{0,3,4,5,6} {0,1,3,6,7}
{0,1,4,5,7}
{0,1,4,6,7}
{0,2,3,6,7}
{0,2,4,6,7}
{0,2,5,6,7}
{0,3,5,6,7}
{0,4,5,6,7}
The a(1) = 1 through a(9) = 24 compositions:
(1) (11) (12) (112) (113) (132) (1114) (1133) (1143)
(21) (121) (122) (231) (1123) (1241) (1332)
(211) (221) (1113) (1132) (1322) (2331)
(311) (1221) (1222) (1412) (3411)
(3111) (1231) (1421) (11115)
(1312) (2141) (11124)
(1321) (2231) (11142)
(2131) (3311) (11241)
(2221) (11114) (11322)
(2311) (11132) (12141)
(3211) (23111) (12222)
(4111) (41111) (12231)
(12312)
(13221)
(14112)
(14121)
(14211)
(21141)
(21321)
(22221)
(22311)
(24111)
(42111)
(51111)
-
fasmin[y_]:=Complement[y,Union@@Table[Union[s,#]&/@Rest[Subsets[Complement[Union@@y,s]]],{s,y}]];
Table[Length[fasmin[Accumulate/@Select[Join@@Permutations/@IntegerPartitions[n],SubsetQ[ReplaceList[#,{_,s__,_}:>Plus[s]],Range[n]]&]]],{n,0,15}]
A325679
Number of compositions of n such that every restriction to a circular subinterval has a different sum.
Original entry on oeis.org
1, 1, 1, 3, 3, 5, 5, 13, 13, 27, 21, 41, 41, 77, 63, 143, 129, 241, 203, 385, 347, 617, 491, 947, 835, 1445, 1185, 2511, 1991, 3585, 2915, 5411, 4569, 8063, 6321, 11131, 10133, 16465, 13207, 23817, 20133, 33929, 26663, 48357, 41363, 69605, 54363, 95727, 81183, 132257, 106581
Offset: 0
The a(1) = 1 through a(8) = 13 compositions:
(1) (2) (3) (4) (5) (6) (7) (8)
(12) (13) (14) (15) (16) (17)
(21) (31) (23) (24) (25) (26)
(32) (42) (34) (35)
(41) (51) (43) (53)
(52) (62)
(61) (71)
(124) (125)
(142) (152)
(214) (215)
(241) (251)
(412) (512)
(421) (521)
-
suball[q_]:=Join[Take[q,#]&/@Select[Tuples[Range[Length[q]],2],OrderedQ],Drop[q,#]&/@Select[Tuples[Range[2,Length[q]-1],2],OrderedQ]];
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],UnsameQ@@Total/@suball[#]&]],{n,0,15}]
-
a(n)={
my(recurse(k,b,w)=
if(k >= n, 1,
b+=1<Andrew Howroyd, Mar 24 2025
A325678
Maximum length of a composition of n such that every restriction to a subinterval has a different sum.
Original entry on oeis.org
0, 1, 1, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10
Offset: 0
-
Table[Max[Length/@Select[Join@@Permutations/@IntegerPartitions[n],UnsameQ@@ReplaceList[#,{_,s__,_}:>Plus[s]]&]],{n,0,15}]
A325686
Number of strict length-3 compositions x + y + z = n satisfying x + y != z and x != y + z.
Original entry on oeis.org
0, 0, 0, 0, 0, 0, 2, 6, 8, 18, 16, 30, 34, 48, 48, 72, 72, 96, 98, 126, 128, 162, 160, 198, 202, 240, 240, 288, 288, 336, 338, 390, 392, 450, 448, 510, 514, 576, 576, 648, 648, 720, 722, 798, 800, 882, 880, 966, 970, 1056, 1056, 1152, 1152, 1248, 1250, 1350, 1352
Offset: 0
The a(6) = 2 through a(10) = 16 compositions:
(132) (124) (125) (126) (127)
(231) (142) (143) (135) (136)
(214) (152) (153) (154)
(241) (215) (162) (163)
(412) (251) (216) (172)
(421) (341) (234) (217)
(512) (243) (253)
(521) (261) (271)
(315) (316)
(324) (352)
(342) (361)
(351) (451)
(423) (613)
(432) (631)
(513) (712)
(531) (721)
(612)
(621)
-
Table[Length[Cases[Join@@Permutations/@IntegerPartitions[n,{3}],{x_,y_,z_}/;x!=y!=z&&x+y!=z &&x!=y+z]],{n,0,30}]
A325681
Number of necklace compositions of n such that every restriction to a circular subinterval has a different sum.
Original entry on oeis.org
1, 1, 2, 2, 3, 3, 6, 6, 11, 9, 16, 16, 27, 23, 46, 42, 73, 63, 112, 102, 173, 141, 254, 228, 373, 313, 614, 500, 855, 709, 1252, 1074, 1827, 1457, 2470, 2260, 3559, 2905, 5044, 4294, 6997, 5623, 9752, 8422, 13741, 10913, 18562, 15912, 25213, 20569, 35146, 29286, 46307, 38241, 61396
Offset: 1
The a(1) = 1 through a(10) = 9 necklace compositions (A = 10):
(1) (2) (3) (4) (5) (6) (7) (8) (9) (A)
(12) (13) (14) (15) (16) (17) (18) (19)
(23) (24) (25) (26) (27) (28)
(34) (35) (36) (37)
(124) (125) (45) (46)
(142) (152) (126) (127)
(135) (136)
(153) (163)
(162) (172)
(234)
(243)
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neckQ[q_]:=Array[OrderedQ[{q,RotateRight[q,#]}]&,Length[q]-1,1,And];
suball[q_]:=Join[Take[q,#]&/@Select[Tuples[Range[Length[q]],2],OrderedQ],Drop[q,#]&/@Select[Tuples[Range[2,Length[q]-1],2],OrderedQ]];
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],neckQ[#]&&UnsameQ@@Total/@suball[#]&]],{n,15}]
-
a(n)={
my(recurse(k,r,b,w)=
if(k >= n, 1/r,
b+=1<Andrew Howroyd, Mar 25 2025
A351699
T(n,k) is the number of non-congruent maximal subsets of a grid of n X k lattice points (k <= n), such that no two points are at the same distance, and the points do not fit into a smaller grid. The size of the subsets is given by A351700. T(n,k) and A351700 are triangles read by rows.
Original entry on oeis.org
1, 1, 1, 1, 2, 1, 1, 1, 5, 10, 1, 5, 28, 7, 21, 2, 19, 8, 104, 330, 2, 1, 4, 70, 15, 110, 574, 1, 3, 30, 272, 205, 4, 71, 563, 1991, 4, 68, 50, 1001, 113, 1130, 4, 76, 383, 9, 8, 362, 35, 1150, 23, 363, 3975, 7, 38, 8, 18, 1082, 415, 2, 638, 7503, 23, 515, 5802, 2, 2, 150, 62, 4238, 120, 1, 55, 1776, 17277, 26, 481, 2388
Offset: 1
The triangle begins:
#
# 1: 1 Counting grids n X k.
( 1 ) Two lines per side length n:
# 2: 2 2 1. for other side k = 1, 2, ...
( 1 1 ) maximal number of points
# 3: 2 3 3 2. number of configurations
( 1 2 1 )
# 4: 3 4 4 4 Example: 28 figures with
( 1 1 5 10 ) 4 points on 5 X 3
# 5: 3 4 4 5 5
( 1 5 28 7 21 )
# 6: 3 4 5 5 5 6
( 2 19 8 104 330 2 )
# 7: 4 5 5 6 6 6 7
( 1 4 70 15 110 574 1 )
# 8: 4 5 5 6 7 7 7 7
( 3 30 272 205 4 71 563 1991 )
# 9: 4 5 6 6 7 7 8 8 8
( 4 68 50 1001 113 1130 4 76 383 )
#10: 4 6 6 7 7 8 8 8 9 9
( 9 8 362 35 1150 23 363 3975 7 38 )
#11: 4 6 6 7 8 8 8 9 9 9 10
( 8 18 1082 415 2 638 7503 23 515 5802 2 )
#
# Grid n X k configurations with
# distinct distances
.
.
All T(6,3) = 8 configurations
0 1 2 3 4 5 0 1 2 3 4 5
------------------- -------------------
2 | . X X . X . 2 | . . . . X .
1 | . . . . . X 1 | . . . . . X
0 | X . . . . . 0 | X . X . . X
y /------------------- y /-------------------
x 0 1 2 3 4 5 x 0 1 2 3 4 5
{1,2,4,5,8,9,10,17,20,26} dist^2 {1,2,4,5,8,9,10,20,25,26}
0 1 2 3 4 5 0 1 2 3 4 5
------------------- -------------------
2 | . . X . X . 2 | . X . X . .
1 | . . . . . X 1 | X . . . . .
0 | X X . . . . 0 | X . . . . X
y /------------------- y /-------------------
x 0 1 2 3 4 5 x 0 1 2 3 4 5
{1,2,4,5,8,10,13,17,20,26} dist^2 {1,2,4,5,8,10,13,20,25,26}
0 1 2 3 4 5 0 1 2 3 4 5
------------------- -------------------
2 | . . . . X . 2 | . . X . X .
1 | X . . . . X 1 | X . . . . X
0 | X . X . . . 0 | X . . . . .
y /------------------- y /-------------------
x 0 1 2 3 4 5 x 0 1 2 3 4 5
{1,2,4,5,8,10,17,20,25,26} dist^2 {1,2,4,5,8,10,17,20,25,26}
0 1 2 3 4 5 0 1 2 3 4 5
------------------- -------------------
2 | . . X . . X 2 | X . . . . X
1 | . . . . . . 1 | . . . . . .
0 | X X . . . X 0 | X . . X X .
y /------------------- y /-------------------
x 0 1 2 3 4 5 x 0 1 2 3 4 5
{1,4,5,8,9,13,16,20,25,29} dist^2 {1,4,5,8,9,13,16,20,25,29}
.
A308251
Number of subsets of {1,...,n + 1} containing n + 1 and such that all positive differences of distinct elements are distinct.
Original entry on oeis.org
1, 2, 3, 6, 9, 14, 21, 34, 49, 76, 101, 146, 205, 294, 397, 560, 747, 1028, 1341, 1810, 2343, 3178, 4051, 5370, 6921, 9014, 11361, 14838, 18719, 24082, 29953, 38220, 47663, 60550, 74619, 93848, 115961, 145320, 177549, 221676, 270335, 335124
Offset: 0
The a(0) = 1 through a(5) = 14 subsets:
{1} {2} {3} {4} {5} {6}
{1,2} {1,3} {1,4} {1,5} {1,6}
{2,3} {2,4} {2,5} {2,6}
{3,4} {3,5} {3,6}
{1,2,4} {4,5} {4,6}
{1,3,4} {1,2,5} {5,6}
{1,4,5} {1,2,6}
{2,3,5} {1,3,6}
{2,4,5} {1,4,6}
{1,5,6}
{2,3,6}
{2,5,6}
{3,4,6}
{3,5,6}
-
Table[Length[Select[Subsets[Range[n]],MemberQ[#,n]&&UnsameQ@@Abs[Subtract@@@Subsets[#,{2}]]&]],{n,15}]
Comments