cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 11 results. Next

A052147 a(n) = prime(n) + 2.

Original entry on oeis.org

4, 5, 7, 9, 13, 15, 19, 21, 25, 31, 33, 39, 43, 45, 49, 55, 61, 63, 69, 73, 75, 81, 85, 91, 99, 103, 105, 109, 111, 115, 129, 133, 139, 141, 151, 153, 159, 165, 169, 175, 181, 183, 193, 195, 199, 201, 213, 225, 229, 231, 235, 241, 243, 253, 259
Offset: 1

Views

Author

Simon Colton (simonco(AT)cs.york.ac.uk), Jan 24 2000

Keywords

Comments

A048974, A052147, A067187 and A088685 are very similar after dropping terms less than 13. - Eric W. Weisstein, Oct 10 2003
A117530(n,2) = a(n) for n>1. - Reinhard Zumkeller, Mar 26 2006
a(n) = A000040(n) + 2 = A008864(n) + 1 = A113395(n) - 1 = A175221(n) - 2 = A175222(n) - 3 = A139049(n) - 4 = A175223(n) - 5 = A175224(n) - 6 = A140353(n) - 7 = A175225(n) - 8. - Jaroslav Krizek, Mar 06 2010
Left edge of the triangle in A065342. - Reinhard Zumkeller, Jan 30 2012
Union of A006512 and A107986. - David James Sycamore, Jul 08 2018

Crossrefs

A139690 is a subsequence.

Programs

A113935 a(n) = prime(n) + 3.

Original entry on oeis.org

5, 6, 8, 10, 14, 16, 20, 22, 26, 32, 34, 40, 44, 46, 50, 56, 62, 64, 70, 74, 76, 82, 86, 92, 100, 104, 106, 110, 112, 116, 130, 134, 140, 142, 152, 154, 160, 166, 170, 176, 182, 184, 194, 196, 200, 202, 214, 226, 230, 232, 236, 242, 244, 254, 260, 266, 272, 274
Offset: 1

Views

Author

Jorge Coveiro, Jan 30 2006

Keywords

Crossrefs

Programs

Formula

a(n) = A116366(n-1,1) for n>1. - Reinhard Zumkeller, Feb 06 2006
a(n) = 2*A098090(n-1) for n > 1. - Reinhard Zumkeller, Sep 14 2006
a(n) = A000040(n) + 3 = A008864(n) + 2 = A052147(n) + 1 = A175221(n) - 1 = A175222(n) - 2 = A139049(n) - 3 = A175223(n) - 4 = A175224(n) - 5 = A140353(n) - 6 = A175225(n) - 7. - Jaroslav Krizek, Mar 06 2010

A140353 a(n) = prime(n) + 9.

Original entry on oeis.org

11, 12, 14, 16, 20, 22, 26, 28, 32, 38, 40, 46, 50, 52, 56, 62, 68, 70, 76, 80, 82, 88, 92, 98, 106, 110, 112, 116, 118, 122, 136, 140, 146, 148, 158, 160, 166, 172, 176, 182, 188, 190, 200, 202, 206, 208, 220, 232, 236, 238, 242, 248, 250, 260, 266, 272, 278, 280, 286
Offset: 1

Views

Author

Odimar Fabeny, May 30 2008

Keywords

Comments

a(n) = A000040(n) + 9 = A008864(n) + 8 = A052147(n) + 7 = A113395(n) + 6 = A175221(n) + 5 = A175222(n) + 4 = A139049(n) + 3 = A175223(n) + 2 = A175224(n) + 1 = A175225(n) - 1. - Jaroslav Krizek, Mar 06 2010

Crossrefs

Programs

  • GAP
    Filtered([1..300], k-> IsPrime(k) ) +9 # G. C. Greubel, May 20 2019
  • Magma
    [NthPrime(n)+9: n in [1..70]]; // G. C. Greubel, May 20 2019
    
  • Mathematica
    9 + Prime[Range[70]] (* G. C. Greubel, May 20 2019 *)
  • PARI
    A140353(n) = prime(n)+9
    
  • Sage
    [nth_prime(n) +9 for n in (1..70)] # G. C. Greubel, May 20 2019
    

Extensions

Edited by Michael B. Porter, Jan 28 2010

A175221 a(n) = prime(n) + 4.

Original entry on oeis.org

6, 7, 9, 11, 15, 17, 21, 23, 27, 33, 35, 41, 45, 47, 51, 57, 63, 65, 71, 75, 77, 83, 87, 93, 101, 105, 107, 111, 113, 117, 131, 135, 141, 143, 153, 155, 161, 167, 171, 177, 183, 185, 195, 197, 201, 203, 215, 227, 231, 233, 237, 243, 245, 255, 261, 267, 273, 275
Offset: 1

Views

Author

Jaroslav Krizek, Mar 06 2010

Keywords

Programs

Formula

a(n) = A000040(n) + 4 = A008864(n) + 3 = A052147(n) + 2 = A113395(n) + 1.
a(n) = A175222(n) - 1 = A139049(n) - 2 = A175223(n) - 3.
a(n) = A175224(n) - 4 = A140353(n) - 5 = A175225(n) - 6.

Extensions

More terms from Vincenzo Librandi, Mar 14 2010

A139049 a(n) = prime(n) + 6.

Original entry on oeis.org

8, 9, 11, 13, 17, 19, 23, 25, 29, 35, 37, 43, 47, 49, 53, 59, 65, 67, 73, 77, 79, 85, 89, 95, 103, 107, 109, 113, 115, 119, 133, 137, 143, 145, 155, 157, 163, 169, 173, 179, 185, 187, 197, 199, 203, 205, 217, 229, 233, 235, 239, 245, 247, 257, 263, 269, 275, 277
Offset: 1

Views

Author

Odimar Fabeny, Jun 02 2008

Keywords

Comments

a(n) = A000040(n) + 6 = A008864(n) + 5 = A052147(n) + 4 = A113395(n) + 3 = A175221(n) + 2 = A175222(n) + 1 = A175223(n) - 1 = A175224(n) - 2 = A140353(n) - 3 = A175225(n) - 4. - Jaroslav Krizek, Mar 06 2010

Crossrefs

Cf. A140353.

Programs

Extensions

Edited by Michael B. Porter, Jan 28 2010

A175223 a(n) = prime(n) + 7.

Original entry on oeis.org

9, 10, 12, 14, 18, 20, 24, 26, 30, 36, 38, 44, 48, 50, 54, 60, 66, 68, 74, 78, 80, 86, 90, 96, 104, 108, 110, 114, 116, 120, 134, 138, 144, 146, 156, 158, 164, 170, 174, 180, 186, 188, 198, 200, 204, 206, 218, 230, 234, 236, 240, 246, 248, 258, 264, 270, 276, 278
Offset: 1

Views

Author

Jaroslav Krizek, Mar 06 2010

Keywords

Comments

a(n) = A000040(n) + 7 = A008864(n) + 6 = A052147(n) + 5 = A113395(n) + 4 = A175221(n) + 3 = A175222 (n) + 2 = A139049(n) + 1 = A175224(n) - 1 = A140353(n) - 2 = A175225(n) - 3.

Programs

Extensions

More terms from Vincenzo Librandi, Mar 14 2010

A175224 a(n) = prime(n) + 8.

Original entry on oeis.org

10, 11, 13, 15, 19, 21, 25, 27, 31, 37, 39, 45, 49, 51, 55, 61, 67, 69, 75, 79, 81, 87, 91, 97, 105, 109, 111, 115, 117, 121, 135, 139, 145, 147, 157, 159, 165, 171, 175, 181, 187, 189, 199, 201, 205, 207, 219, 231, 235, 237, 241, 247, 249, 259, 265, 271, 277, 279
Offset: 1

Views

Author

Jaroslav Krizek, Mar 06 2010

Keywords

Comments

a(n) = A000040(n) + 8 = A008864(n) + 7 = A052147(n) + 6 = A113395(n) + 5 = A175221(n) + 4 = A175222(n) + 3 = A139049(n) + 2 = A175223(n) + 1 = A140353(n) - 1 = A175225(n) - 2.

Crossrefs

Programs

Extensions

More terms from Vincenzo Librandi, Mar 14 2010

A175225 a(n) = prime(n) + 10.

Original entry on oeis.org

12, 13, 15, 17, 21, 23, 27, 29, 33, 39, 41, 47, 51, 53, 57, 63, 69, 71, 77, 81, 83, 89, 93, 99, 107, 111, 113, 117, 119, 123, 137, 141, 147, 149, 159, 161, 167, 173, 177, 183, 189, 191, 201, 203, 207, 209, 221, 233, 237, 239, 243, 249, 251, 261, 267, 273, 279, 281
Offset: 1

Views

Author

Jaroslav Krizek, Mar 06 2010

Keywords

Comments

a(n) = A000040(n) + 10 = A008864(n) + 9 = A052147(n) + 8 = A113395(n) + 7 = A175221(n) + 6 = A175222(n) + 5 = A139049(n) + 4 = A175223(n) + 3 = A175224(n) + 2 = A140353(n) + 1.

Crossrefs

Programs

Extensions

More terms from Vincenzo Librandi, Mar 14 2010

A297925 Even numbers k such that k - 5 is prime but k - 3 is not prime.

Original entry on oeis.org

12, 18, 24, 28, 36, 42, 48, 52, 58, 66, 72, 78, 84, 88, 94, 102, 108, 114, 118, 132, 136, 144, 156, 162, 168, 172, 178, 186, 198, 204, 216, 228, 234, 238, 246, 256, 262, 268, 276, 282, 288, 298, 312, 318, 322, 336, 342, 354, 358, 364, 372, 378, 384, 388, 394, 402, 406, 414, 426, 438, 444, 448, 454
Offset: 1

Views

Author

David James Sycamore, Jan 08 2018

Keywords

Comments

Even numbers that are the sum of 5 and another prime, but not the sum of 3 and another prime. For n >= 1, a(n) - 5 = A049591(n), a(n) - 3 = A107986(n+1).
Let r(n) = a(n) - 5, Then r(n) is the greatest prime < a(n), and therefore A056240(a(n)) = 5*r(n). Furthermore, since r(n) + 2 must be composite, A056240(a(n)) = 5*A049591(n).
The terms in this sequence, combined with those in A298366 and A298252 form a partition of A005843(n);n>=3 (nonnegative even numbers>=6). This is because any even integer n>=6 satisfies either (i) n-3 is prime, (ii) n-5 is prime but n-3 is composite, or (iii) both n-5 and n-3 are composite.

Examples

			12 is a term because 12 - 5 = 7 is prime, and 12 - 3 = 9 is composite. Also A049591(1)+5=7+5=12 and A107986(2)+3=9+3=12.
18 is a term because 18 - 5 = 13 is prime, and 18 - 3 = 15 is composite.
16 is not a term because 16 - 5 = 11 and 16 - 3 = 13 are both prime.
		

Crossrefs

Similar to A130038. Subsequence of A175222.

Programs

  • GAP
    Filtered([8..500], k-> IsPrime(k-5) and not IsPrime(k-3) and (k mod 2)=0); # G. C. Greubel, May 21 2019
  • Magma
    [n: n in [3..500] | IsPrime(n-5) and not IsPrime(n-3) and (n mod 2) eq 0]; // G. C. Greubel, May 21 2019
    
  • Maple
    N:=100
    for n from 8 to N by 2 do
    if isprime(n-5) and not isprime(n-3) then print (n);
    end if
    end do
  • Mathematica
    Select[Range[6, 500, 2], And[PrimeQ[# - 5], ! PrimeQ[# - 3]] &] (* Michael De Vlieger, Jan 10 2018 *)
    Select[Range[6, 500, 2], Boole[PrimeQ[# -{5, 3}]] == {1, 0} &] (* Harvey P. Dale, Jan 30 2024 *)
  • PARI
    isok(n) = !(n % 2) && isprime(n-5) && !isprime(n-3); \\ Michel Marcus, Jan 09 2018
    
  • Sage
    [n for n in (3..500) if is_prime(n-5) and not is_prime(n-3) and (mod(n, 2)==0)] # G. C. Greubel, May 21 2019
    

Formula

a(n) = A049591(n) + 5 = A107986(n+1) + 3 for all n >= 1.

A173064 a(n) = prime(n) - 5.

Original entry on oeis.org

0, 2, 6, 8, 12, 14, 18, 24, 26, 32, 36, 38, 42, 48, 54, 56, 62, 66, 68, 74, 78, 84, 92, 96, 98, 102, 104, 108, 122, 126, 132, 134, 144, 146, 152, 158, 162, 168, 174, 176, 186, 188, 192, 194, 206, 218, 222, 224, 228, 234, 236, 246, 252, 258, 264, 266, 272, 276, 278, 288, 302, 306, 308, 312, 326, 332, 342, 344, 348, 354, 362, 368, 374, 378, 384, 392, 396, 404
Offset: 3

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    [NthPrime(n) - 5: n in [3..100]]; // G. C. Greubel, May 19 2019
    
  • Mathematica
    Prime[Range[3,120]] - 5
  • PARI
    {a(n) = prime(n) - 5}; \\ G. C. Greubel, May 19 2019
    
  • Sage
    [nth_prime(n) - 5 for n in (3..100)] # G. C. Greubel, May 19 2019
Showing 1-10 of 11 results. Next