A014499 -id:A014499 - cp's OEIS frontend

A372687 Number of prime numbers whose binary indices sum to n. Number of strict integer partitions y of n such that Sum_i 2^(y_i-1) is prime.

0, 0, 1, 1, 1, 0, 2, 1, 2, 0, 3, 3, 1, 4, 1, 6, 5, 8, 4, 12, 8, 12, 7, 20, 8, 16, 17, 27, 19, 38, 19, 46, 33, 38, 49, 65, 47, 67, 83, 92, 94, 113, 103, 130, 146, 127, 215, 224, 176, 234, 306, 270, 357, 383, 339, 393, 537, 540, 597, 683, 576, 798, 1026, 830, 1157

Offset: 0

Gus Wiseman, May 15 2024

nonn

A binary index of n is any position of a 1 in its reversed binary expansion. The binary indices of n are row n of A048793.

Note the inverse of A048793 (binary indices) takes a set s to Sum_i 2^(s_i-1).

			The a(2) = 1 through a(17) = 8 prime numbers:
  2  3  5  .  17  11  19  .  257  131  73  137  97  521  4099  1031
              7       13     67   41       71       263  2053  523
                             37   23       43       139  1033  269
                                           29       83   193   163
                                                    53   47    149
                                                    31         101
                                                               89
                                                               79
The a(2) = 1 through a(11) = 3 strict partitions:
  (2)  (2,1)  (3,1)  .  (5,1)    (4,2,1)  (4,3,1)  .  (9,1)    (6,4,1)
                        (3,2,1)           (5,2,1)     (6,3,1)  (8,2,1)
                                                      (7,2,1)  (5,3,2,1)

For all positive integers (not just prime) we get A000009.
Number of prime numbers p with A029931(p) = n.
For odd instead of prime we have A096765, even A025147, non-strict A087787
Number of times n appears in A372429.
Number of rows of A372471 with sum n.
The non-strict version is A372688 (or A372887), ranks A277319 (or A372850).
These (strict) partitions have Heinz numbers A372851.
A014499 lists binary indices of prime numbers.
A019565 gives Heinz number of binary indices, adjoint A048675.
A038499 counts partitions of prime length, strict A085756.
A048793 lists binary indices:
- length A000120
- min A001511
- sum A029931
- max A070939
- reverse A272020
A058698 counts partitions of prime numbers, strict A064688.
A096111 gives product of binary indices.
A372689 lists numbers whose binary indices sum to a prime.
A372885 lists primes whose binary indices sum to a prime, indices A372886.
Cf. A000040, A005940, A023506, A029837, A035100, A071814, A230877, A231204, A359359, A372436, A372441.

Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&PrimeQ[Total[2^#]/2]&]],{n,0,30}]

A372850 Numbers whose distinct prime indices are the binary indices of some prime number.

Original entry on oeis.org

3, 6, 9, 10, 12, 18, 20, 22, 24, 27, 30, 36, 40, 42, 44, 46, 48, 50, 54, 60, 66, 70, 72, 80, 81, 84, 88, 90, 92, 96, 100, 102, 108, 114, 118, 120, 126, 130, 132, 140, 144, 150, 160, 162, 168, 176, 180, 182, 184, 192, 198, 200, 204, 216, 228, 236, 238, 240, 242

Offset: 1

Gus Wiseman, May 16 2024

nonn

A binary index of n is any position of a 1 in its reversed binary expansion. The binary indices of n are row n of A048793.
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
Note the function taking a set s to its rank Sum_i 2^(s_i-1) is the inverse of A048793 (binary indices).

			The distinct prime indices of 45 are {2,3}, which are the binary indices of 6, which is not prime, so 45 is not in the sequence.
The distinct prime indices of 60 are {1,2,3}, which are the binary indices of 7, which is prime, so 60 is in the sequence.
The terms together with their prime indices begin:
    3: {2}
    6: {1,2}
    9: {2,2}
   10: {1,3}
   12: {1,1,2}
   18: {1,2,2}
   20: {1,1,3}
   22: {1,5}
   24: {1,1,1,2}
   27: {2,2,2}
   30: {1,2,3}
   36: {1,1,2,2}
   40: {1,1,1,3}
   42: {1,2,4}
   44: {1,1,5}
   46: {1,9}
   48: {1,1,1,1,2}
   50: {1,3,3}
   54: {1,2,2,2}
   60: {1,1,2,3}
   66: {1,2,5}
   70: {1,3,4}

For even instead of prime we have A005408, with multiplicity A003159.
For odd instead of prime we have  A005843, with multiplicity A036554.
For prime indices with multiplicity we have A277319, counted by A372688.
The squarefree case is A372851, counted by A372687.
Partitions of this type are counted by A372887.
A014499 lists binary indices of prime numbers.
A019565 gives Heinz number of binary indices, adjoint A048675.
A038499 counts partitions of prime length, strict A085756.
A048793 and A272020 (reverse) list binary indices:
- length A000120
- min A001511
- sum A029931
- max A070939
A058698 counts partitions of prime numbers, strict A064688.
A372885 lists primes whose binary indices sum to a prime, indices A372886.
Cf. A000040, A005940, A023506, A029837, A035100, A071814, A096111, A372429, A372436, A372441, A372471, A372689.

prix[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
Select[Range[100],PrimeQ[Total[2^(Union[prix[#]]-1)]]&]

Numbers k such that Sum_{i:prime(i)|k} 2^(i-1) is prime, where the sum is over the distinct prime indices of k.

A372851 Squarefree numbers whose prime indices are the binary indices of some prime number.

Original entry on oeis.org

3, 6, 10, 22, 30, 42, 46, 66, 70, 102, 114, 118, 130, 182, 238, 246, 266, 318, 330, 354, 370, 402, 406, 434, 442, 510, 546, 646, 654, 690, 762, 770, 798, 930, 938, 946, 962, 986, 1066, 1102, 1122, 1178, 1218, 1222, 1246, 1258, 1334, 1378, 1430, 1482, 1578

Offset: 1

Gus Wiseman, May 16 2024

nonn

A binary index of n is any position of a 1 in its reversed binary expansion. The binary indices of n are row n of A048793.
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
Note the function taking a set s to its rank Sum_i 2^(s_i-1) is the inverse of A048793 (binary indices).

			The prime indices of 70 are {1,3,4}, which are the binary indices of 13, which is prime, so 70 is in the sequence.
The prime indices of 15 are {2,3}, which are the binary indices of 6, which is not prime, so 15 is not in the sequence.
The terms together with their prime indices begin:
    3: {2}
    6: {1,2}
   10: {1,3}
   22: {1,5}
   30: {1,2,3}
   42: {1,2,4}
   46: {1,9}
   66: {1,2,5}
   70: {1,3,4}
  102: {1,2,7}
  114: {1,2,8}
  118: {1,17}
  130: {1,3,6}
  182: {1,4,6}
  238: {1,4,7}
  246: {1,2,13}
  266: {1,4,8}
  318: {1,2,16}
  330: {1,2,3,5}
  354: {1,2,17}
  370: {1,3,12}
  402: {1,2,19}

[Warning: do not confuse A372887 with the strict case A372687.]
For odd instead of prime we have A039956.
For even instead of prime we have A056911.
Strict partitions of this type are counted by A372687.
Non-strict partitions of this type are counted by A372688, ranks A277319.
The nonsquarefree version is A372850, counted by A372887.
A014499 lists binary indices of prime numbers.
A019565 gives Heinz number of binary indices, adjoint A048675.
A038499 counts partitions of prime length, strict A085756.
A048793 and A272020 (reverse) list binary indices:
- length A000120
- min A001511
- sum A029931
- max A070939
A058698 counts partitions of prime numbers, strict A064688.
A372885 lists primes whose binary indices sum to a prime, indices A372886.
Cf. A000040, A005940, A025147, A035100, A071814, A096111, A096765, A231204, A372429, A372471, A372689.

Select[Range[100],SquareFreeQ[#] && PrimeQ[Total[2^(PrimePi/@First/@FactorInteger[#]-1)]]&]

Squarefree numbers k such that Sum_{i:prime(i)|k} 2^(i-1) is prime, where the sum is over the (distinct) prime indices of k.

A065049 Odd primes of incorrect parity: number of 1's in the binary representation of n (mod 2) == 1 - (n mod 3) (mod 2). Also called isolated primes.

Original entry on oeis.org

11, 41, 43, 47, 59, 107, 131, 137, 139, 163, 167, 173, 179, 191, 227, 233, 239, 251, 277, 337, 349, 373, 419, 431, 443, 491, 521, 523, 547, 557, 563, 569, 571, 587, 617, 619, 641, 643, 647, 653, 659, 673, 677, 691, 701, 719, 739, 743, 751, 761, 809, 811

Offset: 1

Robert G. Wilson v, Nov 06 2001

"The prime maze - consider the prime numbers in base 2, starting with the smallest prime (10)2. One can move to another prime number by either changing only one digit of the number, or adding a 1 to the front of the number. Can we reach 11 = (1011)2.? 333? The Mersennes?" - Caldwell

			47 is in the sequence because 47d = 101111b which has five 1's in its binary notation; an odd number. Also 47 == 2 (mod 3); an even number. Therefore a mismatch exists.

Robert Israel, Table of n, a(n) for n = 1..10000
Chris K. Caldwell, Prime Links + +
W. Paulsen, The Prime Maze, Fib. Quart., 40 (2002), 272-279.
C. Rivera, Problem 25 - William Paulsen's Prime Numbers Maze

Cf. A000120, A014499.

filter:= proc(n) convert(convert(n,base,2),`+`) + (n mod 3) mod 2 = 1 end proc:
select(filter, [seq(ithprime(i),i=2..1000)]); # Robert Israel, Jun 19 2018

Select[ Range[3, 1000, 2], PrimeQ[ # ] && EvenQ[ Count[ IntegerDigits[ #, 2], 1]] == OddQ[ Mod[ #, 3]] & ]

isok(p) = (p>2) && isprime(p) && ((hammingweight(p) % 2) != ((p % 3) % 2)); \\ Michel Marcus, Dec 15 2018

A090455 Difference between numbers of binary 1's of n and binary 1's of n-th prime.

Original entry on oeis.org

0, -1, 0, -2, -1, -1, 1, -2, -2, -2, -2, -1, 0, -1, -1, -3, -3, -3, 0, -2, 0, -2, 0, -2, 0, -1, -1, -2, -1, 0, -2, -2, -1, -2, -1, -3, -2, -1, -1, -3, -2, -2, -3, 0, 0, -1, 0, -5, -2, -2, -1, -4, -1, -3, 3, -1, 0, -1, 1, 0, 0, 1, 1, -5, -3, -4, -2, -2, -3, -3, 0, -4, -4, -3

Offset: 1

Reinhard Zumkeller, Dec 01 2003

Amiram Eldar, Table of n, a(n) for n = 1..10000

Cf. A000120, A014499.
Cf. A007088, A004676, A090431.
Cf. A049084, A071600, A090456, A090457.

Table[DigitCount[n,2,1]-DigitCount[Prime[n],2,1],{n,80}] (* Harvey P. Dale, Aug 08 2013 *)

a(n) = A000120(n) - A014499(n);
a(A071600(n)) = a(A049084(A072439(n))) = 0.
a(A049084(A090456(n))) < 0.
a(A049084(A090457(n))) > 0.

Definition clarified by Harvey P. Dale, Aug 08 2013

A177796 Numbers n such that number of 1's in binary representation of n-th prime = number of 0's in binary representation of n-th prime.

Original entry on oeis.org

1, 12, 13, 34, 35, 38, 45, 100, 102, 103, 104, 107, 110, 112, 113, 118, 119, 120, 121, 123, 127, 138, 140, 158, 323, 328, 331, 335, 339, 345, 348, 350, 353, 355, 356, 359, 365, 366, 380, 385, 393, 394, 396, 398, 412, 414, 415, 419, 425, 456, 472, 484

Offset: 1

Juri-Stepan Gerasimov, May 14 2010

nonn

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Cf. A031443, A014499, A035103.

n1Q[n_]:=Module[{idn2=IntegerDigits[Prime[n],2]},Count[idn2,1] == Length[idn2]/2]; Select[Range[500],n1Q] (* Harvey P. Dale, Jun 26 2013 *)

is(n)=n=prime(n);hammingweight(n)==hammingweight(bitneg(n, #binary(n))) \\ Charles R Greathouse IV, Mar 29 2013

A014499(a(n))=A035103(a(n)).

Entries checked by D. S. McNeil, Nov 26 2010

A372887 Number of integer partitions of n whose distinct parts are the binary indices of some prime number.

Original entry on oeis.org

0, 0, 1, 1, 3, 3, 6, 8, 12, 14, 21, 29, 36, 48, 56, 74, 94, 123, 144, 195, 235, 301, 356, 456, 538, 679, 803, 997, 1189, 1467, 1716, 2103, 2488, 2968, 3517, 4185, 4907, 5834, 6850, 8032, 9459, 11073, 12933, 15130, 17652, 20480, 24011, 27851, 32344, 37520

Offset: 0

Gus Wiseman, May 19 2024

nonn

A binary index of n is any position of a 1 in its reversed binary expansion. The binary indices of n are row n of A048793.

Note the inverse of A048793 (binary indices) takes a set s to Sum_i 2^(s_i-1).

			The partition y = (4,3,1,1) has distinct parts {1,3,4}, which are the binary indices of 13, which is prime, so y is counted under a(9).
The a(2) = 1 through a(9) = 14 partitions:
  (2)  (21)  (22)   (221)   (51)     (331)     (431)      (3321)
             (31)   (311)   (222)    (421)     (521)      (4221)
             (211)  (2111)  (321)    (511)     (2222)     (4311)
                            (2211)   (2221)    (3221)     (5211)
                            (3111)   (3211)    (3311)     (22221)
                            (21111)  (22111)   (4211)     (32211)
                                     (31111)   (5111)     (33111)
                                     (211111)  (22211)    (42111)
                                               (32111)    (51111)
                                               (221111)   (222111)
                                               (311111)   (321111)
                                               (2111111)  (2211111)
                                                          (3111111)
                                                          (21111111)

For odd instead of prime we have A000041, even A002865.
The strict case is A372687, ranks A372851.
Counting not just distinct parts gives A372688, ranks A277319.
These partitions have Heinz numbers A372850.
A014499 lists binary indices of prime numbers.
A019565 gives Heinz number of binary indices, adjoint A048675.
A058698 counts partitions of prime numbers, strict A064688.
A372689 lists numbers whose binary indices sum to a prime.
A372885 lists primes whose binary indices sum to a prime, indices A372886.
Binary indices:
- listed A048793, sum A029931
- reversed A272020
- opposite A371572, sum A230877
- length A000120, complement A023416
- min A001511, opposite A000012
- max A070939, opposite A070940
- complement A368494, sum A359400
- opposite complement A371571, sum A359359
Cf. A000040, A000041, A029837, A035100, A038499, A372429, A372471.

Table[Length[Select[IntegerPartitions[n], PrimeQ[Total[2^(Union[#]-1)]]&]],{n,0,30}]

A072578 In binary representation: k has the same number of 0's as the k-th prime has 1's.

Original entry on oeis.org

8, 16, 34, 44, 64, 65, 80, 106, 116, 128, 138, 140, 174, 178, 184, 193, 196, 209, 258, 259, 260, 263, 264, 266, 272, 280, 288, 290, 314, 316, 325, 326, 327, 328, 330, 338, 344, 385, 391, 402, 449, 514, 520, 521, 528, 544, 566, 570, 574, 578, 587, 590, 597

Offset: 1

Reinhard Zumkeller, Jun 23 2002

			In binary representation 80 = '1010000' has five 0's and A000040(80) = 409 = '110011001' has five 1's: therefore 80 is a term.

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Harvey P. Dale)

Cf. A000120, A014499, A023416, A049084, A071600, A072577, A072579, A072581.

Select[Range[600],DigitCount[#,2,0]==DigitCount[Prime[#],2,1]&] (* Harvey P. Dale, Jan 07 2014 *)

A000120(A072581(n)) = A023416(a(n)) = A014499(n).

a(n) = A049084(A072581(n)).

A072581 a(n) = A000040(A072578(n)).

Original entry on oeis.org

19, 53, 139, 193, 311, 313, 409, 577, 641, 719, 787, 809, 1033, 1061, 1097, 1171, 1193, 1289, 1627, 1637, 1657, 1669, 1693, 1699, 1747, 1811, 1877, 1889, 2083, 2089, 2153, 2161, 2179, 2203, 2213, 2273, 2311, 2659, 2689, 2753, 3169, 3677, 3727, 3733

Offset: 1

Reinhard Zumkeller, Jun 23 2002

			In binary representation 80 = '1010000' has five 0's and A000040(80) = 409 = '110011001' has five 1's: therefore 409 is a term.

Amiram Eldar, Table of n, a(n) for n = 1..10000

Cf. A000040, A000120, A014499, A023416, A072439, A072578, A072580, A072582, A072584.

With[{m = 600}, Select[Transpose[{Range[m], Prime[Range[m]]}], DigitCount[First[#], 2, 0] == DigitCount[Last[#], 2, 1] &]][[;; , 2]] (* Amiram Eldar, Jul 28 2025 *)

A000120(a(n)) = A023416(A072578(n)) = A014499(n).

A095376 Values of k such that the total number of 1's in the binary expansions of the first k integers is a multiple of k.

Original entry on oeis.org

1, 2, 14, 62, 65, 77, 254, 322, 323, 327, 331, 332, 1022, 1281, 1341, 1348, 1349, 1350, 1352, 1353, 1354, 4094, 16382, 21505, 21757, 21762, 21820, 65534, 87299, 87355, 262142, 348161, 349181, 1048574, 1397762, 1398012, 1398020, 1398074, 4194302

Offset: 1

Labos Elemer, Jun 07 2004

All numbers of the form 4^k-2, with k>0, appear in this sequence. - Paul Tek, Sep 24 2013

			k=14: {1, 10, 11, 10, 101, 110, 111, 1000, 1001, 1010, 1011, 1100, 1101, 1110} includes 28 1's so A000788(14)/14 = 2 is an integer, thus 14 is here.

Donovan Johnson, Table of n, a(n) for n = 1..100

Cf. A000120, A000788, A014499, A095375.

lib[x_] := Count[IntegerDigits[x, 2], 1]; {s=0, ta=Table[0, {100}], tb=Table[0, {100}], u=1}; Do[s=s+lib[n]; w=n; If[IntegerQ[s/n], Print[{n, s/n}]; ta[[u]]=n; tb[[u]]=s/n; u=u+1], {n, 100000}]

Integer solutions to {A000788(x)/x is an integer}.

cp's OEIS Frontend

A372687 Number of prime numbers whose binary indices sum to n. Number of strict integer partitions y of n such that Sum_i 2^(y_i-1) is prime.

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A372850 Numbers whose distinct prime indices are the binary indices of some prime number.

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A372851 Squarefree numbers whose prime indices are the binary indices of some prime number.

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A065049 Odd primes of incorrect parity: number of 1's in the binary representation of n (mod 2) == 1 - (n mod 3) (mod 2). Also called isolated primes.

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A090455 Difference between numbers of binary 1's of n and binary 1's of n-th prime.

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A177796 Numbers n such that number of 1's in binary representation of n-th prime = number of 0's in binary representation of n-th prime.

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A372887 Number of integer partitions of n whose distinct parts are the binary indices of some prime number.

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A072578 In binary representation: k has the same number of 0's as the k-th prime has 1's.

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