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.

Previous Showing 11-19 of 19 results.

A037034 Least k such that 4*n*k-1 is a prime.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 3, 1, 2, 2, 1, 1, 2, 3, 1, 2, 1, 1, 2, 1, 1, 3, 4, 2, 2, 1, 1, 2, 3, 2, 5, 1, 1, 2, 1, 3, 3, 1, 2, 3, 1, 1, 5, 7, 1, 2, 3, 1, 3, 1, 5, 5, 1, 2, 2, 1, 1, 2, 13, 1, 2, 3, 1, 5, 4, 1, 6, 1, 3, 3, 1, 3, 5, 3, 2, 2, 1, 1, 2, 4, 2, 3, 1, 7, 3, 3, 1, 5, 4, 1, 2, 1, 2, 2, 1, 1, 3, 4, 3, 5, 6, 3, 2, 4
Offset: 1

Views

Author

Felice Russo

Keywords

Examples

			a(5)=1 because 4*5*1-1=19 is a prime

Links

Crossrefs

Cf. A016014.

Programs

  • Mathematica
    lk[n_]:=Module[{c=4n,k=1},While[!PrimeQ[c*k-1],k++];k]; Array[lk,110] (* Harvey P. Dale, Jun 05 2012 *)

Extensions

More terms from Erich Friedman

A365958 Least k such that 8*n*k+1 is a prime.

Original entry on oeis.org

2, 1, 3, 3, 1, 2, 2, 3, 1, 3, 1, 1, 3, 1, 2, 2, 1, 3, 3, 4, 2, 2, 7, 1, 2, 6, 2, 2, 1, 1, 6, 1, 5, 5, 1, 2, 2, 4, 1, 2, 7, 1, 3, 1, 5, 9, 3, 2, 8, 1, 1, 3, 4, 1, 2, 1, 1, 2, 4, 7, 2, 3, 2, 15, 1, 4, 3, 10, 3, 5, 1, 1, 3, 1, 1, 2, 1, 2, 6, 1, 2, 12, 3, 1, 2
Offset: 1

Views

Author

Robert Price, Dec 17 2023

Keywords

Links

Crossrefs

Cf. A016014, A005123.
A070852 lists the corresponding primes.

Programs

  • Mathematica
    A365958 = {};
Do[k=1; While[!PrimeQ[8 n k+1], k++]; AppendTo[A365958 ,k], {n,85}];
A365958
  • PARI
    a(n) = my(k=1); while (!isprime(8*n*k+1), k++); k; \\ Michel Marcus, Dec 17 2023

A366931 Least k such that 3*n*k+1 is a prime.

Original entry on oeis.org

2, 1, 2, 1, 2, 1, 2, 3, 4, 1, 2, 1, 2, 1, 4, 2, 2, 2, 4, 1, 2, 1, 2, 1, 2, 1, 2, 4, 4, 2, 4, 1, 2, 1, 2, 1, 2, 2, 8, 2, 6, 1, 8, 3, 2, 1, 2, 3, 6, 1, 2, 1, 20, 1, 2, 2, 12, 2, 4, 1, 2, 2, 2, 1, 6, 1, 8, 2, 4, 1, 4, 2, 2, 1, 8, 1, 2, 4, 6, 1, 2, 3, 2, 3, 4, 4
Offset: 1

Views

Author

Robert Price, Dec 17 2023

Keywords

Links

Crossrefs

Cf. A016014, A024892.
A070847 lists the corresponding primes.

Programs

  • Mathematica
    A366931 = {};
Do[k=1; While[!PrimeQ[3 n k+1], k++]; AppendTo[A366931 ,k], {n,85}];
A366931
lkp[n_]:=Module[{k=1},While[!PrimeQ[3n*k+1],k++];k]; Array[lkp,90] (* Harvey P. Dale, Jan 09 2025 *)
  • PARI
    a(n) = my(k=1); while (!isprime(3*n*k+1), k++); k; \\ Michel Marcus, Dec 17 2023

A367970 Least k such that 5*n*k+1 is a prime.

Original entry on oeis.org

2, 1, 2, 2, 4, 1, 2, 1, 4, 2, 6, 1, 2, 1, 2, 3, 12, 2, 2, 1, 2, 3, 4, 2, 2, 1, 2, 2, 10, 1, 2, 4, 2, 6, 4, 1, 8, 1, 6, 2, 4, 1, 2, 3, 8, 2, 4, 1, 2, 1, 4, 2, 4, 1, 12, 1, 2, 5, 4, 2, 6, 1, 2, 2, 4, 1, 6, 3, 2, 2, 6, 5, 18, 4, 2, 2, 6, 3, 6, 1, 2, 2, 28, 1, 6
Offset: 1

Views

Author

Robert Price, Dec 17 2023

Keywords

Links

Crossrefs

Cf. A016014, A024894.
A070849 lists the corresponding primes.

Programs

  • Mathematica
    A367970 = {};
Do[k=1; While[!PrimeQ[5 n k+1], k++]; AppendTo[A367970 ,k], {n,85}];
A367970
  • PARI
    a(n) = my(k=1); while (!isprime(5*n*k+1), k++); k; \\ Michel Marcus, Dec 17 2023

A368201 Least k such that 9*n*k+1 is a prime.

Original entry on oeis.org

2, 1, 4, 1, 4, 2, 2, 1, 2, 2, 2, 1, 8, 1, 2, 3, 2, 1, 12, 1, 2, 1, 4, 2, 8, 4, 2, 3, 2, 1, 4, 2, 6, 1, 2, 4, 6, 6, 10, 5, 2, 1, 4, 1, 2, 2, 4, 1, 2, 4, 2, 2, 14, 1, 2, 2, 4, 1, 2, 1, 14, 2, 4, 1, 2, 3, 12, 1, 6, 1, 2, 2, 6, 3, 6, 3, 6, 5, 2, 3, 2, 1, 6, 1, 2
Offset: 1

Views

Author

Robert Price, Dec 16 2023

Keywords

Links

Crossrefs

Cf. A016014, A024906.
A070853 lists the corresponding primes.

Programs

  • Mathematica
    A368201 = {};
Do[k=1; While[!PrimeQ[9 n k+1], k++]; AppendTo[A368201,k], {n,85}];
A368201
  • PARI
    a(n) = my(k=1); while (!isprime(9*n*k+1), k++); k; \\ Michel Marcus, Dec 16 2023

A368202 Least k such that 6*n*k+1 is a prime.

Original entry on oeis.org

1, 1, 1, 3, 1, 1, 1, 2, 2, 1, 1, 1, 1, 4, 2, 1, 1, 1, 2, 2, 1, 3, 1, 3, 1, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2, 1, 1, 4, 1, 3, 3, 4, 5, 1, 1, 1, 2, 3, 2, 1, 1, 10, 4, 1, 1, 6, 1, 2, 5, 1, 1, 1, 2, 3, 1, 4, 1, 2, 1, 2, 1, 1, 4, 4, 1, 1, 2, 3, 7, 1, 6, 1, 2, 2, 2
Offset: 1

Views

Author

Robert Price, Dec 16 2023

Keywords

Links

Crossrefs

Cf. A016014, A024899.
A070850 lists the corresponding primes.

Programs

  • Mathematica
    A368202 = {};
Do[k=1; While[!PrimeQ[9 n k+1], k++]; AppendTo[A368202, k], {n, 86}];
A368202
  • PARI
    a(n) = my(k=1); while (!isprime(6*n*k+1), k++); k; \\ Michel Marcus, Dec 16 2023

A368203 Least k such that 7*n*k+1 is a prime.

Original entry on oeis.org

4, 2, 2, 1, 2, 1, 4, 2, 2, 1, 6, 4, 6, 2, 2, 1, 2, 1, 12, 2, 6, 3, 6, 2, 4, 3, 2, 1, 12, 1, 6, 2, 2, 1, 2, 3, 10, 6, 2, 1, 6, 3, 10, 2, 2, 3, 2, 1, 4, 2, 4, 3, 2, 1, 6, 8, 4, 6, 2, 1, 4, 3, 2, 1, 2, 1, 4, 2, 2, 1, 14, 2, 6, 5, 2, 3, 12, 1, 4, 5, 4, 3, 2, 6
Offset: 1

Views

Author

Robert Price, Dec 16 2023

Keywords

Links

Crossrefs

Cf. A016014, A024905.
A070851 lists the corresponding primes.

Programs

  • Mathematica
    A368203 = {};
Do[k=1; While[!PrimeQ[7 n k+1], k++]; AppendTo[A368203,k], {n,84}];
A368203
  • PARI
    a(n) = my(k=1); while (!isprime(7*n*k+1), k++); k; \\ Michel Marcus, Dec 16 2023

A037036 Least k such that 2^n+1-k is a prime.

Original entry on oeis.org

0, 0, 0, 2, 0, 2, 4, 2, 0, 4, 4, 10, 4, 2, 4, 20, 0, 2, 6, 2, 4, 10, 4, 16, 4, 40, 6, 40, 58, 4, 36, 2, 6, 10, 42, 32, 6, 26, 46, 8, 88, 22, 12, 58, 18, 56, 22, 116, 60, 82, 28, 130, 48, 112, 34, 56, 6, 14, 28, 56, 94, 2, 58, 26, 60, 50, 6, 20, 24, 20, 36, 232, 94, 70, 36, 98, 16, 34
Offset: 0

Views

Author

Felice Russo

Keywords

Examples

			a(5)=2 because 2^5+1-2=31 that is a prime.

Crossrefs

Cf. A016014.

Programs

  • PARI
    a(n) = my(k = 0); while (! isprime(2^n+1-k), k++); k; \\ Michel Marcus, Sep 28 2013

Extensions

More terms from Erich Friedman

A037039 Least k such that 4*n*k+1 is a prime.

Original entry on oeis.org

1, 2, 1, 1, 2, 3, 1, 3, 1, 1, 2, 2, 1, 2, 1, 3, 2, 1, 3, 3, 4, 1, 3, 1, 1, 3, 1, 1, 2, 2, 3, 2, 3, 1, 2, 3, 1, 3, 1, 4, 5, 2, 1, 2, 1, 7, 5, 1, 1, 2, 2, 6, 5, 2, 3, 2, 1, 1, 3, 1, 3, 6, 3, 1, 2, 5, 1, 5, 1, 1, 2, 2, 1, 2, 2, 4, 2, 1, 1, 2, 4, 7, 3, 1, 3, 3, 1, 1, 3, 5, 3, 9, 1, 3, 2, 2, 1, 8, 1, 1, 2, 1, 3, 3, 1
Offset: 1

Views

Author

Felice Russo

Keywords

Examples

			a(5)=2 because for n=5: 4*5*2+1=41 is a prime.

Crossrefs

Cf. A016014.

Programs

  • Mathematica
    Table[Module[{k=1},While[!PrimeQ[4 n*k+1],k++];k],{n,110}] (* Harvey P. Dale, Aug 11 2025 *)
  • PARI
    a(n) = my(k = 0); while (! isprime(4*n*k+1), k++); k; \\ Michel Marcus, Sep 28 2013

Extensions

More terms from Erich Friedman
Previous Showing 11-19 of 19 results.

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