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 1-4 of 4 results.

A253970 Primes p such that p + nextprime(p) is divisible by 5.

Original entry on oeis.org

2, 13, 29, 43, 47, 59, 103, 113, 149, 157, 163, 167, 179, 193, 199, 223, 239, 257, 269, 293, 313, 367, 401, 419, 463, 491, 509, 557, 569, 587, 599, 607, 613, 619, 643, 647, 659, 673, 677, 701, 727, 761, 773, 809, 823, 853, 863, 883, 911, 947, 953, 977, 1019
Offset: 1

Views

Author

Vincenzo Librandi, Jan 23 2015

Keywords

Comments

Primes p such that p + nextprime(p) is divisible by 10 is the same as this sequence without the term 2. - Derek Orr, Jan 30 2015

Examples

			p=29 is in this sequence because 29+31 = 60 is divisible by 5.
		

Crossrefs

Cf. similar sequences listed in A253969.

Programs

  • Magma
    [p: p in PrimesUpTo(1500) | (p+NextPrime(p)) mod 5 eq 0];
    
  • Mathematica
    Prime@Select[Range[300], Mod[Prime[#] + Prime[# + 1], 5]==0 &]
    Transpose[Select[Partition[Prime[Range[200]],2,1],Divisible[Total[ #],5]&]] [[1]] (* Harvey P. Dale, Feb 10 2015 *)
  • PARI
    forprime(p=1,10^3,if(!((p+nextprime(p+1))%5),print1(p,", "))) \\ Derek Orr, Jan 30 2015

A253972 Primes p such that p + nextprime(p) is divisible by 8.

Original entry on oeis.org

3, 11, 53, 59, 61, 71, 73, 107, 113, 139, 157, 173, 179, 191, 227, 233, 239, 257, 283, 293, 311, 317, 347, 353, 373, 419, 431, 433, 523, 541, 547, 557, 593, 599, 601, 631, 653, 659, 677, 691, 733, 773, 787, 811, 827, 919, 941, 953, 977, 1013, 1019, 1031, 1033
Offset: 1

Views

Author

Vincenzo Librandi, Jan 23 2015

Keywords

Examples

			p=59 is in this sequence because 59+61 = 120 is divisible by 8.
		

Crossrefs

Cf. similar sequences listed in A253969.

Programs

  • Magma
    [p: p in PrimesUpTo(1500) | (p+NextPrime(p)) mod 8 eq 0];
    
  • Mathematica
    Prime@Select[Range[300], Mod[Prime[#] + Prime[# + 1], 8]==0 &]
    Select[Partition[Prime[Range[200]],2,1],Mod[Total[#],8]==0&][[;;,1]] (* Harvey P. Dale, Aug 28 2024 *)
  • PARI
    forprime(p=1,10^3,if(!((p+nextprime(p+1))%8),print1(p,", "))) \\ Derek Orr, Jan 30 2015

A253973 Primes p such that p + nextprime(p) is divisible by 9.

Original entry on oeis.org

7, 17, 43, 71, 79, 97, 107, 139, 179, 197, 223, 269, 277, 283, 313, 317, 337, 349, 401, 409, 431, 439, 457, 491, 521, 673, 743, 761, 787, 809, 827, 839, 853, 881, 907, 1021, 1039, 1061, 1087, 1151, 1193, 1213, 1277, 1303, 1373, 1399, 1429, 1447, 1471, 1483
Offset: 1

Views

Author

Vincenzo Librandi, Jan 28 2015

Keywords

Examples

			p=43 is in this sequence because 43+47 = 90 is divisible by 9.
		

Crossrefs

Cf. similar sequences listed in A253969.

Programs

  • Magma
    [p: p in PrimesUpTo(1500) | (p+NextPrime(p)) mod 9 eq 0];
    
  • Mathematica
    Prime@Select[Range[300], Mod[Prime[#] + Prime[# + 1], 9]==0 &]
    Select[Partition[Prime[Range[300]],2,1],Divisible[Total[#],9]&][[All,1]] (* Harvey P. Dale, Jul 27 2017 *)
  • PARI
    forprime(p=1,10^3,if(!((p+nextprime(p+1))%9),print1(p,", "))) \\ Derek Orr, Jan 30 2015

A348578 Primes that begin a record list of consecutive primes whose sum of any 2 consecutive terms is divisible by 3.

Original entry on oeis.org

5, 89, 809, 3954889, 15186319, 77011289, 288413159, 62585146739, 114058236679, 143014298809, 2320700383121, 2942277160583, 4386778243843, 16104860854333, 23171469790747
Offset: 1

Views

Author

Michel Marcus, Oct 24 2021

Keywords

Comments

The Rivera link gives the first 15 terms.

Examples

			A001043 begins as (5, 8, 12, 18, 24, 30, 36, 42, 52) where 7 consecutive terms are multiple of 3 starting at 3rd term, corresponding to 5=prime(3), so 5 is the 1st term of this sequence.
		

Crossrefs

Programs

  • Mathematica
    p=2;t=r=0;Monitor[Do[p=NextPrime[p];t=0;While[Mod[p+NextPrime@p,3]==0,p=NextPrime@p;t++];If[t>r,Print[NextPrime[p,-t]];r=t],{n,10^14}],p] (* Giorgos Kalogeropoulos, Oct 24 2021 *)
Showing 1-4 of 4 results.