A007522 -id:A007522 - cp's OEIS frontend

A089199 Primes p such that p+1 is divisible by a cube.

7, 23, 31, 47, 53, 71, 79, 103, 107, 127, 151, 167, 191, 199, 223, 239, 263, 269, 271, 311, 359, 367, 383, 431, 439, 463, 479, 487, 499, 503, 593, 599, 607, 631, 647, 701, 719, 727, 743, 751, 809, 823, 839, 863, 887, 911, 919, 967, 971, 983, 991

Offset: 1

Cino Hilliard, Dec 08 2003

This sequence is infinite and its relative density in the sequence of primes is equal to 1 - Product_{p prime} (1-1/(p^2*(p-1))) = 1 - A065414 = 0.302498... (Mirsky, 1949). - Amiram Eldar, Apr 07 2021

Robert Israel, Table of n, a(n) for n = 1..10000
Leon Mirsky, The number of representations of an integer as the sum of a prime and a k-free integer, The American Mathematical Monthly, Vol. 56, No. 1 (1949), pp. 17-19.

Includes A007522 and A141965.

Cf. A049098, A065414.

filter:= proc(p)
  isprime(p) and ormap(t -> t[2]>=3, ifactors(p+1)[2])
end proc:
select(filter, [seq(i,i=3..2000,2)]); # Robert Israel, Jan 11 2019

f[n_]:=Max[Last/@FactorInteger[n]]; lst={};Do[p=Prime[n];If[f[p+1]>=3,AppendTo[lst,p]],{n,6!}];lst (* Vladimir Joseph Stephan Orlovsky, Oct 03 2009 *)

ispowerfree(m,p1) = { flag=1; y=component(factor(m),2); for(i=1,length(y), if(y[i] >= p1,flag=0;break); ); return(flag) }
powerfreep3(n,p,k) = { c=0; pc=0; forprime(x=2,n, pc++; if(ispowerfree(x+k,p)==0, c++; print1(x","); ) ); print(); print(c","pc","c/pc+.0) }

A101792 Primes of the form 8k-1 such that 4k-1 and 16*k-1 are also primes.

Original entry on oeis.org

23, 359, 719, 1439, 2039, 2063, 2903, 3023, 3623, 3863, 4919, 5399, 5639, 6983, 7079, 7823, 10799, 12263, 14159, 14303, 21383, 22343, 22943, 24239, 25799, 25919, 33623, 34319, 36383, 38639, 39983, 40823, 42023, 42359, 44543, 46199, 47639, 48479, 49103, 54959

Offset: 1

Douglas Stones (dssto1(AT)student.monash.edu.au), Dec 16 2004

			4*3 - 1 = 11, 8*3 - 1 = 23 and 16*3 - 1 = 47 are primes, so 23 is a term.

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

Cf. A002515, A101790, A101791, A101793.
Subsequence of A007522.
Subsequences: A101796, A101996.

8 * Select[Range[10^4], And @@ PrimeQ[2^Range[2, 4]*# - 1] &] - 1 (* Amiram Eldar, May 13 2024 *)

for(k=1,7000,if(isprime(8*k-1)&&isprime(4*k-1)&&isprime(16*k-1),print1(8*k-1,", "))) \\ Hugo Pfoertner, Sep 07 2021

a(n) = 8*A101790(n) - 1 = 2*A101791(n) + 1. - Amiram Eldar, May 13 2024

A127591 Numbers k such that 64k+21 is prime.

Original entry on oeis.org

2, 4, 10, 13, 17, 19, 20, 22, 23, 25, 29, 32, 37, 44, 50, 53, 55, 58, 59, 62, 68, 79, 83, 88, 89, 94, 95, 97, 100, 107, 109, 113, 118, 122, 134, 142, 143, 152, 155, 157, 158, 163, 167, 169, 173, 193, 194, 199, 200

Offset: 1

Artur Jasinski, Jan 19 2007

nonn

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Cf. A035050, A007522, A127575, A127576, A127577, A127578, A127580, A127581, A087522, A127586, A127587, A127589, A127590, A127592, A127593, A127594.

a = {}; Do[If[PrimeQ[21 + 64 n], AppendTo[a, n]], {n, 0, 200}]; a
Select[Range[200],PrimeQ[64#+21]&] (* Harvey P. Dale, Jan 15 2016 *)

A127592 Primes of the form 64k+21.

Original entry on oeis.org

149, 277, 661, 853, 1109, 1237, 1301, 1429, 1493, 1621, 1877, 2069, 2389, 2837, 3221, 3413, 3541, 3733, 3797, 3989, 4373, 5077, 5333, 5653, 5717, 6037, 6101, 6229, 6421, 6869, 6997, 7253, 7573, 7829, 8597, 9109, 9173, 9749, 9941, 10069, 10133, 10453

Offset: 1

Artur Jasinski, Jan 19 2007, Nov 12 2007

All these primes are sums of two squares, also all indices are sums of two squares since we have the identity 64k+21 = 4(4(4k+1)+1)+1.

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Cf. A000040. A035050, A007522, A127575, A127576, A127577, A127578, A127580, A127581, A087522, A127586, A127587, A127589, A127590, A127591, A127593, A127594.

[p: p in PrimesUpTo(11000) | p mod 64 eq 21 ]; // Vincenzo Librandi, Sep 06 2012

a = {}; Do[If[PrimeQ[21 + 64 n], AppendTo[a, 21 + 64 n]], {n, 0, 200}]; a
Select[Prime[Range[1700]], MemberQ[{21}, Mod[#, 64]] &] (* Vincenzo Librandi, Sep 06 2012 *)

A065909 First solution mod p of x^4 = 2 for primes p such that more than two solutions exist.

Original entry on oeis.org

18, 5, 27, 28, 35, 46, 131, 48, 252, 104, 45, 123, 51, 9, 69, 77, 51, 177, 472, 261, 55, 117, 224, 562, 12, 264, 273, 132, 127, 500, 17, 197, 107, 36, 206, 671, 127, 159, 137, 684, 329, 564, 316, 314, 197, 98, 661, 925, 461, 170, 930, 151, 1081, 333, 434, 924

Offset: 1

Klaus Brockhaus, Nov 29 2001

nonn

Conjecture: no integer occurs more than three time in this sequence. Confirmed for the first 1182 terms of A014754 (primes < 100000). There are integers which do occur thrice, e.g. 6624. Moreover, no integer is first, second, third or fourth solution for more than three primes. Confirmed for the first 2399 terms of A007522 and the first 1182 terms of A014754 (primes < 100000).

			a(3) = 27, since 113 is the third term of A014754, 27, 47, 66 and 86 are the solutions mod 113 of x^4 = 2 and 27 is the least one.

Cf. A040098, A007522, A014754, A065910, A065911, A065912.

a065909(m) = local(s); forprime(p = 2,m,s = []; for(x = 0,p-1, if(x^4%p == 2%p,s = concat(s,[x]))); if(matsize(s)[2]>2,print1(s[1],",")))
a065909(4000)

a(n) = first (least) solution mod p of x^4 = 2, where p is the n-th prime such that x^4 = 2 has more than two solutions mod p, i.e. p is the n-th term of A014754.

Definition corrected by Harvey P. Dale, Apr 16 2015

A065910 Second solution mod p of x^4 = 2 for primes p such that more than two solution exists.

Original entry on oeis.org

25, 8, 47, 71, 46, 91, 158, 102, 278, 294, 216, 201, 355, 110, 297, 283, 161, 567, 490, 422, 578, 250, 309, 625, 344, 578, 287, 151, 164, 641, 736, 238, 474, 763, 408, 758, 406, 650, 813, 1090, 1043, 771, 328, 699, 902, 165, 857, 1000, 553, 1148, 1434, 955

Offset: 1

Klaus Brockhaus, Nov 29 2001

nonn

Conjecture: no integer occurs more than three time in this sequence. Confirmed for the first 1182 terms of A014754 (primes < 100000). In this section, there are no integers which do occur thrice. Moreover, no integer is first, second, third or fourth solution for more than three primes. Confirmed for the first 2399 terms of A007522 and the first 1182 terms of A014754 (primes < 100000).

			a(3) = 47, since 113 is the third term of A014754, 27, 47, 66 and 86 are the solutions mod 113 of x^4 = 2 and 47 is the second one.

Cf. A040098, A007522, A014754, A065909, A065911, A065912.

a065910(m) = local(s); forprime(p = 2,m,s = []; for(x = 0,p-1, if(x^4%p == 2%p,s = concat(s,[x]))); if(matsize(s)[2]>2,print1(s[2],",")))
a065910(3500)

a(n) = second solution mod p of x^4 = 2, where p is the n-th prime such that x^4 = 2 has more than two solutions mod p, i.e. p is the n-th term of A014754.

A065911 Third solution mod p of x^4 = 2 for primes p such that more than two solution exists.

Original entry on oeis.org

48, 81, 66, 162, 211, 190, 179, 251, 299, 299, 385, 416, 526, 827, 736, 766, 936, 586, 703, 779, 639, 999, 980, 808, 1137, 975, 1314, 1458, 1557, 1112, 1041, 1563, 1415, 1150, 1681, 1355, 1723, 1623, 1468, 1303, 1398, 1702, 2265, 1958, 1787, 2668, 2000

Offset: 1

Klaus Brockhaus, Nov 29 2001

nonn

Conjecture: no integer occurs more than three time in this sequence. Confirmed for the first 1182 terms of A014754 (primes < 100000). In this section, there are no integers which do occur thrice. Moreover, no integer is first, second, third or fourth solution for more than three primes. Confirmed for the first 2399 terms of A007522 and the first 1182 terms of A014754 (primes < 100000).

			a(3) = 66, since 113 is the third term of A014754, 27, 47, 66 and 86 are the solutions mod 113 of x^4 = 2 and 66 is the third one.

Cf. A040098, A007522, A014754, A065909, A065910, A065912.

a065911(m) = local(s); forprime(p = 2,m,s = []; for(x = 0,p-1, if(x^4%p == 2%p,s = concat(s,[x]))); if(matsize(s)[2]>2,print1(s[3],",")))
a065911(3000)

a(n) = third solution mod p of x^4 = 2, where p is the n-th prime such that x^4 = 2 has more than two solutions mod p, i.e. p is the n-th term of A014754.

A065912 Fourth solution mod p of x^4 = 2 for primes p such that more than two solution exists.

Original entry on oeis.org

55, 84, 86, 205, 222, 235, 206, 305, 325, 489, 556, 494, 830, 928, 964, 972, 1046, 976, 721, 940, 1162, 1132, 1065, 871, 1469, 1289, 1328, 1477, 1594, 1253, 1760, 1604, 1782, 1877, 1883, 1442, 2002, 2114, 2144, 1709, 2112, 1909, 2277, 2343, 2492, 2735

Offset: 1

Klaus Brockhaus, Nov 29 2001

nonn

Conjecture: no integer occurs more than three time in this sequence. Confirmed for the first 1182 terms of A014754 (primes < 100000). In this section, there are no integers which do occur thrice. Moreover, no integer is first, second, third or fourth solution for more than three primes. Confirmed for the first 2399 terms of A007522 and the first 1182 terms of A014754 (primes < 100000).

			a(3) = 86, since 113 is the third term of A014754, 27, 47, 66 and 86 are the solutions mod 113 of x^4 = 2 and 86 is the fourth one.

Cf. A040098, A007522, A014754, A065909, A065910, A065911.

a065912(m) = local(s); forprime(p = 2,m,s = []; for(x = 0,p-1, if(x^4%p == 2%p,s = concat(s,[x]))); if(matsize(s)[2]>3,print1(s[4],",")))
a065912(3000)

a(n) = fourth solution mod p of x^4 = 2, where p is the n-th prime such that x^4 = 2 has more than two solutions mod p, i.e. p is the n-th term of A014754.

A127593 Primes of the form 256 k + 85.

Original entry on oeis.org

853, 1109, 1621, 1877, 2389, 3413, 5717, 6229, 6997, 7253, 10069, 10837, 11093, 12373, 13397, 16981, 17749, 18517, 18773, 19541, 21589, 22613, 23893, 24917, 27733, 29269, 30293, 31573, 32341, 37717, 39509, 40277, 41813, 43093, 46933

Offset: 1

Artur Jasinski, Jan 19 2007

nonn

Cf. A035050, A007522, A127575, A127576, A127577, A127578, A127580, A127581, A087522, A127586, A127587, A127589, A127590, A127591, A127592, A127594.

a = {}; Do[If[PrimeQ[85 + 256 n], AppendTo[a, 85 + 256 n]], {n, 0, 200}]; a
Select[256*Range[200]+85,PrimeQ] (* Harvey P. Dale, Oct 09 2020 *)

A127594 Numbers k such that 256 k + 85 is prime.

Original entry on oeis.org

3, 4, 6, 7, 9, 13, 22, 24, 27, 28, 39, 42, 43, 48, 52, 66, 69, 72, 73, 76, 84, 88, 93, 97, 108, 114, 118, 123, 126, 147, 154, 157, 163, 168, 183, 184, 186, 196, 198

Offset: 1

Artur Jasinski, Jan 19 2007

nonn

Cf. A035050, A007522, A127575, A127576, A127577, A127578, A127580, A127581, A087522, A127586, A127587, A127589, A127590, A127591, A127592, A127593.

a = {}; Do[If[PrimeQ[85 + 256 n], AppendTo[a, n]], {n, 0, 200}]; a

cp's OEIS Frontend

A089199 Primes p such that p+1 is divisible by a cube.

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A101792 Primes of the form 8*k-1 such that 4*k-1 and 16*k-1 are also primes.

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A127591 Numbers k such that 64k+21 is prime.

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A127592 Primes of the form 64k+21.

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A065909 First solution mod p of x^4 = 2 for primes p such that more than two solutions exist.

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A065910 Second solution mod p of x^4 = 2 for primes p such that more than two solution exists.

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A065911 Third solution mod p of x^4 = 2 for primes p such that more than two solution exists.

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A065912 Fourth solution mod p of x^4 = 2 for primes p such that more than two solution exists.

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A101792 Primes of the form 8k-1 such that 4k-1 and 16*k-1 are also primes.