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 1-5 of 5 results.

A377510 a(n) = number of iterations of x -> 2 x + 5 to reach a nonprime, starting with prime(n).

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Oct 31 2024

Keywords

Comments

See A377120 for a guide to related sequences.

Examples

			prime(6) = 13 -> 31 -> 67 -> 139 -> 283 -> 571 -> 1147 = 31*37, so a(6) = 6.

Crossrefs

Cf. A377120, A377511, A377512, A377513, A377514.

Programs

  • Mathematica
    Table[p = Prime[n]; c = 1; While[p = 2*p + 5; PrimeQ[p], c++]; c, {n, 200}]

A377511 a(n) = number of iterations of x -> 2 x + 7 to reach a nonprime, starting with prime(n).

Original entry on oeis.org

3, 2, 4, 1, 2, 1, 3, 1, 4, 1, 1, 1, 2, 1, 2, 3, 1, 1, 1, 2, 1, 1, 3, 1, 1, 1, 1, 1, 1, 2, 1, 2, 3, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 3, 1, 1, 1, 3, 1, 1, 1, 1, 2, 3, 1, 1, 1, 1, 2, 1, 5, 1, 1, 1, 3, 1, 1, 3, 1, 1, 1, 1, 1, 1, 3, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Clark Kimberling, Oct 31 2024

Keywords

Comments

See A377120 for a guide to related sequences.

Examples

			prime(3) = 5 -> 17 -> 41 -> 89 -> 185 = 5*37, so a(3) = 4.

Crossrefs

Cf. A377120, A377510, A377512, A377513, A377514.

Programs

  • Mathematica
    Table[p = Prime[n]; c = 1; While[p = 2*p + 7; PrimeQ[p], c++]; c, {n, 200}]

A377512 a(n) = number of iterations of x -> 2 x - 3 to reach a nonprime, starting with prime(n).

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Nov 05 2024

Keywords

Comments

See A377120 for a guide to related sequences.

Examples

			prime(3) = 5 -> 7 -> 11 -> 19 -> 35 = 5*7, so a(1) = 4.

Crossrefs

Cf. A377120, A377510, A377511, A377513, A377514.

Programs

  • Mathematica
    Table[p = Prime[n]; c = 1; While[p = 2*p + 7; PrimeQ[p], c++]; c, {n, 200}]

A377513 a(n) = number of iterations of x -> 2 x - 5 to reach a nonprime, starting with prime(n+4).

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Nov 05 2024

Keywords

Comments

See A377120 for a guide to related sequences.

Examples

			prime(5) = 11 -> 17 -> 29 -> 53 -> 101 -> 197 -> 389 -> 773 -> 1541 = 23*67,
so a(1) = 8.

Crossrefs

Cf. A377120, A377510, A377511, A377512, A377514.

Programs

  • Mathematica
    Table[p = Prime[n + 4]; c = 1; While[p = 2*p - 5; PrimeQ[p], c++]; c, {n, 200}]

A377514 a(n) = number of iterations of x -> 2 x - 7 to reach a nonprime, starting with prime(n+4).

Original entry on oeis.org

1, 3, 1, 2, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 2, 1, 3, 2, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 2, 1, 1, 3, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 2, 1, 3, 1, 1, 1, 1, 2, 1, 1, 4, 3, 2, 1, 1, 3, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 3
Offset: 1

Views

Author

Clark Kimberling, Nov 05 2024

Keywords

Comments

See A377120 for a guide to related sequences.

Examples

			prime(6) = 13 -> 19 -> 31 -> 55 = 5*11, so a(2) = 3.

Crossrefs

Cf. A377120, A377510, A377511, A377512, A377513.

Programs

  • Mathematica
    Table[p = Prime[n + 4]; c = 1; While[p = 2*p - 7; PrimeQ[p], c++]; c, {n, 200}]
Showing 1-5 of 5 results.

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