A352131
Number of strict integer partitions of n with same number of even parts as odd conjugate parts.
Original entry on oeis.org
1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 2, 1, 1, 2, 3, 2, 2, 3, 4, 3, 4, 5, 5, 5, 6, 7, 7, 8, 10, 10, 10, 12, 14, 15, 14, 17, 21, 20, 20, 25, 28, 28, 29, 34, 39, 39, 40, 47, 52, 53, 56, 64, 70, 71, 77, 86, 92, 97, 104, 114, 122
Offset: 0
The a(n) strict partitions for selected n:
n = 3 10 14 18 21 24
----------------------------------------------------------------------
(2,1) (6,4) (8,6) (10,8) (11,10) (8,7,5,4)
(4,3,2,1) (5,4,3,2) (6,5,4,3) (8,6,4,3) (9,8,4,3)
(6,5,2,1) (7,6,3,2) (8,7,4,2) (10,8,4,2)
(8,7,2,1) (10,8,2,1) (10,9,3,2)
(6,5,4,3,2,1) (11,10,2,1)
(8,6,4,3,2,1)
A130780 counts partitions with no more even than odd parts, strict
A239243.
A171966 counts partitions with no more odd than even parts, strict
A239240.
There are four statistics:
There are four other pairings of statistics:
There are three double-pairings of statistics:
Cf.
A027187,
A027193,
A103919,
A122111,
A236559,
A325039,
A344607,
A344651,
A345196,
A350942,
A350950,
A350951.
-
conj[y_]:=If[Length[y]==0,y,Table[Length[Select[y,#>=k&]],{k,1,Max[y]}]];
Table[Length[Select[IntegerPartitions[n],UnsameQ@@#&&Count[#,?EvenQ]==Count[conj[#],?OddQ]&]],{n,0,30}]
A352141
Numbers whose prime factorization has all even indices and all even exponents.
Original entry on oeis.org
1, 9, 49, 81, 169, 361, 441, 729, 841, 1369, 1521, 1849, 2401, 2809, 3249, 3721, 3969, 5041, 6241, 6561, 7569, 7921, 8281, 10201, 11449, 12321, 12769, 13689, 16641, 17161, 17689, 19321, 21609, 22801, 25281, 26569, 28561, 29241, 29929, 32761, 33489, 35721
Offset: 1
The terms together with their prime indices begin:
1 = 1
9 = prime(2)^2
49 = prime(4)^2
81 = prime(2)^4
169 = prime(6)^2
361 = prime(8)^2
441 = prime(2)^2 prime(4)^2
729 = prime(2)^6
841 = prime(10)^2
1369 = prime(12)^2
1521 = prime(2)^2 prime(6)^2
1849 = prime(14)^2
2401 = prime(4)^4
2809 = prime(16)^2
3249 = prime(2)^2 prime(8)^2
3721 = prime(18)^2
3969 = prime(2)^4 prime(4)^2
The second condition alone (all even exponents) is
A000290, counted by
A035363.
The restriction to primes is
A031215.
These partitions are counted by
A035444.
A352140 = even indices with odd exponents, counted by
A055922 aerated.
Cf.
A000720,
A028260,
A055396,
A061395,
A181819,
A195017,
A241638,
A268335,
A276078,
A324524,
A324525,
A324588,
A325698,
A325700,
A352143.
-
Select[Range[1000],#==1||And@@EvenQ/@PrimePi/@First/@FactorInteger[#]&&And@@EvenQ/@Last/@FactorInteger[#]&]
-
from itertools import count, islice
from sympy import factorint, primepi
def A352141_gen(startvalue=1): # generator of terms >= startvalue
return filter(lambda k:all(map(lambda x: not (x[1]%2 or primepi(x[0])%2), factorint(k).items())),count(max(startvalue,1)))
A352141_list = list(islice(A352141_gen(),30)) # Chai Wah Wu, Mar 18 2022
A352140
Numbers whose prime factorization has all even prime indices and all odd exponents.
Original entry on oeis.org
1, 3, 7, 13, 19, 21, 27, 29, 37, 39, 43, 53, 57, 61, 71, 79, 87, 89, 91, 101, 107, 111, 113, 129, 131, 133, 139, 151, 159, 163, 173, 181, 183, 189, 193, 199, 203, 213, 223, 229, 237, 239, 243, 247, 251, 259, 263, 267, 271, 273, 281, 293, 301, 303, 311, 317
Offset: 1
The terms together with their prime indices begin:
1 = 1
3 = prime(2)^1
7 = prime(4)^1
13 = prime(6)^1
19 = prime(8)^1
21 = prime(4)^1 prime(2)^1
27 = prime(2)^3
29 = prime(10)^1
37 = prime(12)^1
39 = prime(6)^1 prime(2)^1
43 = prime(14)^1
53 = prime(16)^1
57 = prime(8)^1 prime(2)^1
61 = prime(18)^1
71 = prime(20)^1
The restriction to primes is
A031215.
These partitions are counted by
A055922 (aerated).
Cf.
A000720,
A028260,
A055396,
A061395,
A181819,
A195017,
A241638,
A276078,
A324517,
A324524,
A324525,
A325698.
-
Select[Range[100],And@@EvenQ/@PrimePi/@First/@FactorInteger[#]&&And@@OddQ/@Last/@FactorInteger[#]&]
-
from sympy import factorint, primepi
def ok(n):
if n%2 == 0: return False
return all(primepi(p)%2==0 and e%2==1 for p, e in factorint(n).items())
print([k for k in range(318) if ok(k)]) # Michael S. Branicky, Mar 12 2022
A366846
Numbers whose odd prime indices are relatively prime.
Original entry on oeis.org
2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 55, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 85, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122
Offset: 1
The odd prime indices of 115 are {3,9}, and these are not relatively prime, so 115 is not in the sequence.
The odd prime indices of 825 are {3,3,5}, and these are relatively prime, so 825 is in the sequence.
The complement when including even indices is
A318978, counted by
A018783.
The nonzero complement ranks the partitions counted by
A366842.
The version for halved even indices is
A366847.
The partitions with these Heinz numbers are counted by
A366850.
Cf.
A000720,
A055396,
A061395,
A066208,
A087436,
A302696,
A302697,
A325698,
A366843,
A366844,
A366849.
A349150
Heinz numbers of integer partitions with at most one odd part.
Original entry on oeis.org
1, 2, 3, 5, 6, 7, 9, 11, 13, 14, 15, 17, 18, 19, 21, 23, 26, 27, 29, 31, 33, 35, 37, 38, 39, 41, 42, 43, 45, 47, 49, 51, 53, 54, 57, 58, 59, 61, 63, 65, 67, 69, 71, 73, 74, 77, 78, 79, 81, 83, 86, 87, 89, 91, 93, 95, 97, 98, 99, 101, 103, 105, 106, 107, 109
Offset: 1
The terms and their prime indices begin:
1: {} 23: {9} 49: {4,4}
2: {1} 26: {1,6} 51: {2,7}
3: {2} 27: {2,2,2} 53: {16}
5: {3} 29: {10} 54: {1,2,2,2}
6: {1,2} 31: {11} 57: {2,8}
7: {4} 33: {2,5} 58: {1,10}
9: {2,2} 35: {3,4} 59: {17}
11: {5} 37: {12} 61: {18}
13: {6} 38: {1,8} 63: {2,2,4}
14: {1,4} 39: {2,6} 65: {3,6}
15: {2,3} 41: {13} 67: {19}
17: {7} 42: {1,2,4} 69: {2,9}
18: {1,2,2} 43: {14} 71: {20}
19: {8} 45: {2,2,3} 73: {21}
21: {2,4} 47: {15} 74: {1,12}
These are the positions of 0's and 1's in
A257991.
The conjugate partitions are ranked by
A349151.
A122111 is a representation of partition conjugation.
A300063 ranks partitions of odd numbers, counted by
A058695 up to 0's.
A316524 gives the alternating sum of prime indices (reverse:
A344616).
A325698 ranks partitions with as many even as odd parts, counted by
A045931.
A345958 ranks partitions with alternating sum 1.
A349157 ranks partitions with as many even parts as odd conjugate parts.
Cf.
A000290,
A000700,
A001222,
A027187,
A027193,
A028260,
A035363,
A047993,
A215366,
A257992,
A277579,
A326841.
-
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
Select[Range[100],Count[Reverse[primeMS[#]],_?OddQ]<=1&]
A351979
Numbers whose prime factorization has all odd prime indices and all even prime exponents.
Original entry on oeis.org
1, 4, 16, 25, 64, 100, 121, 256, 289, 400, 484, 529, 625, 961, 1024, 1156, 1600, 1681, 1936, 2116, 2209, 2500, 3025, 3481, 3844, 4096, 4489, 4624, 5329, 6400, 6724, 6889, 7225, 7744, 8464, 8836, 9409, 10000, 10609, 11881, 12100, 13225, 13924, 14641, 15376
Offset: 1
The terms together with their prime indices begin:
1: 1
4: prime(1)^2
16: prime(1)^4
25: prime(3)^2
64: prime(1)^6
100: prime(1)^2 prime(3)^2
121: prime(5)^2
256: prime(1)^8
289: prime(7)^2
400: prime(1)^4 prime(3)^2
484: prime(1)^2 prime(5)^2
529: prime(9)^2
625: prime(3)^4
961: prime(11)^2
1024: prime(1)^10
1156: prime(1)^2 prime(7)^2
1600: prime(1)^6 prime(3)^2
1681: prime(13)^2
1936: prime(1)^4 prime(5)^2
The second condition alone (exponents all even) is
A000290, counted by
A035363.
The distinct prime factors of terms all come from
A031368.
The first condition alone (indices all odd) is
A066208, counted by
A000009.
A352140 = even indices with odd exponents, counted by
A055922 (aerated).
Cf.
A000720,
A028260,
A045931,
A055396,
A061395,
A106529,
A181819,
A195017,
A276078,
A324588,
A325698,
A325700.
-
Select[Range[1000],#==1||And@@OddQ/@PrimePi/@First/@FactorInteger[#]&&And@@EvenQ/@Last/@FactorInteger[#]&]
-
from sympy import factorint, primepi
def ok(n):
return all(primepi(p)%2==1 and e%2==0 for p, e in factorint(n).items())
print([k for k in range(15500) if ok(k)]) # Michael S. Branicky, Mar 12 2022
A352128
Number of strict integer partitions of n with (1) as many even parts as odd parts, and (2) as many even conjugate parts as odd conjugate parts.
Original entry on oeis.org
1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 2, 0, 2, 2, 3, 0, 3, 0, 2, 2, 5, 2, 5, 4, 6, 7, 7, 8, 8, 9, 9, 13, 9, 14, 12, 20, 13, 25, 17, 33, 23, 40, 26, 50, 33, 59, 39, 68, 45, 84, 58, 92, 70, 115, 88, 132, 109, 156, 139, 182, 172, 212, 211
Offset: 0
The a(n) strict partitions for selected n:
n = 3 18 22 28 31 32
-----------------------------------------------------------------------
(2,1) (8,5,3,2) (8,6,5,3) (12,7,5,4) (10,7,5,4,3,2) (12,8,7,5)
(8,6,3,1) (8,7,5,2) (12,8,5,3) (10,7,6,5,2,1) (12,9,7,4)
(12,7,2,1) (12,9,5,2) (10,8,5,4,3,1) (16,9,4,3)
(16,9,2,1) (10,9,6,3,2,1) (12,10,7,3)
(12,10,5,1) (12,11,7,2)
(16,11,4,1)
A130780 counts partitions with no more even than odd parts, strict
A239243.
A171966 counts partitions with no more odd than even parts, strict
A239240.
There are four statistics:
There are four other pairings of statistics:
There are two other double-pairings of statistics:
Cf.
A000070,
A014105,
A088218,
A098123,
A195017,
A236559,
A236914,
A241638,
A325700,
A350839,
A350941.
-
conj[y_]:=If[Length[y]==0,y,Table[Length[Select[y,#>=k&]],{k,1,Max[y]}]];
Table[Length[Select[IntegerPartitions[n],UnsameQ@@#&&Count[#,?OddQ]==Count[#,?EvenQ]&&Count[conj[#],?OddQ]==Count[conj[#],?EvenQ]&]],{n,0,30}]
A366849
Odd numbers whose halved even prime indices are relatively prime.
Original entry on oeis.org
3, 9, 15, 21, 27, 33, 39, 45, 51, 57, 63, 69, 75, 81, 87, 91, 93, 99, 105, 111, 117, 123, 129, 135, 141, 147, 153, 159, 165, 171, 177, 183, 189, 195, 201, 203, 207, 213, 219, 225, 231, 237, 243, 247, 249, 255, 261, 267, 273, 279, 285, 291, 297, 301, 303, 309
Offset: 1
The even prime indices of 91 are {4,6}, halved {2,3}, which are relatively prime, so 91 is in the sequence.
The prime indices of 665 are {3,4,8}, even {4,8}, halved {2,4}, which are not relatively prime, so 665 is not in the sequence.
The terms together with their prime indices begin:
3: {2}
9: {2,2}
15: {2,3}
21: {2,4}
27: {2,2,2}
33: {2,5}
39: {2,6}
45: {2,2,3}
51: {2,7}
57: {2,8}
63: {2,2,4}
69: {2,9}
75: {2,3,3}
81: {2,2,2,2}
87: {2,10}
91: {4,6}
93: {2,11}
99: {2,2,5}
For odd instead of halved even prime indices we have
A366848.
A348617
Numbers whose sum of prime indices is twice their negated alternating sum.
Original entry on oeis.org
1, 10, 39, 88, 115, 228, 259, 306, 517, 544, 620, 783, 793, 870, 1150, 1204, 1241, 1392, 1656, 1691, 1722, 1845, 2369, 2590, 2596, 2775, 2944, 3038, 3277, 3280, 3339, 3498, 3692, 3996, 4247, 4440, 4935, 5022, 5170, 5226, 5587, 5644, 5875, 5936, 6200, 6321
Offset: 1
The terms and their prime indices begin:
1: ()
10: (3,1)
39: (6,2)
88: (5,1,1,1)
115: (9,3)
228: (8,2,1,1)
259: (12,4)
306: (7,2,2,1)
517: (15,5)
544: (7,1,1,1,1,1)
620: (11,3,1,1)
783: (10,2,2,2)
793: (18,6)
870: (10,3,2,1)
1150: (9,3,3,1)
1204: (14,4,1,1)
1241: (21,7)
1392: (10,2,1,1,1,1)
1656: (9,2,2,1,1,1)
1691: (24,8)
These partitions are counted by
A001523 up to 0's.
The reverse nonnegative version is
A349160, counted by
A006330 up to 0's.
A346697 adds up odd-indexed prime indices.
A346698 adds up even-indexed prime indices.
Cf.
A000984,
A001700,
A028260,
A045931,
A120452,
A195017,
A257991,
A257992,
A262977,
A325698,
A344619,
A345958.
-
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
ats[y_]:=Sum[(-1)^(i-1)*y[[i]],{i,Length[y]}];
Select[Range[1000],Total[primeMS[#]]==-2*ats[primeMS[#]]&]
A352143
Numbers whose prime indices and conjugate prime indices are all odd.
Original entry on oeis.org
1, 2, 5, 8, 11, 17, 20, 23, 31, 32, 41, 44, 47, 59, 67, 68, 73, 80, 83, 92, 97, 103, 109, 124, 125, 127, 128, 137, 149, 157, 164, 167, 176, 179, 188, 191, 197, 211, 227, 233, 236, 241, 257, 268, 269, 272, 275, 277, 283, 292, 307, 313, 320, 331, 332, 347, 353
Offset: 1
The terms together with their prime indices begin:
1: {}
2: {1}
5: {3}
8: {1,1,1}
11: {5}
17: {7}
20: {1,1,3}
23: {9}
31: {11}
32: {1,1,1,1,1}
41: {13}
44: {1,1,5}
47: {15}
59: {17}
67: {19}
68: {1,1,7}
73: {21}
80: {1,1,1,1,3}
The restriction to primes is
A031368.
These partitions appear to be counted by
A053253.
For even instead of odd conjugate parts we get
A066208^2.
The first condition alone (all odd indices) is
A066208, counted by
A000009.
A238745 gives the Heinz number of the conjugate prime signature.
A352140 = even indices and odd multiplicities, counted by
A055922 aerated.
Cf.
A000290,
A000701,
A000720,
A028260,
A045931,
A046682,
A055396,
A061395,
A195017,
A241638,
A325698,
A325700.
-
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
conj[y_]:=If[Length[y]==0,y,Table[Length[Select[y,#>=k&]],{k,1,Max[y]}]];
Select[Range[100],And@@OddQ/@primeMS[#]&&And@@OddQ/@conj[primeMS[#]]&]
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