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.

A087489 Primes p such that 3^p - 2^p is composite.

Original entry on oeis.org

7, 11, 13, 19, 23, 37, 41, 43, 47, 61, 67, 71, 73, 79, 83, 89, 97, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 281, 283, 293, 307, 311, 313, 317
Offset: 1

Views

Author

Cino Hilliard, Oct 26 2003

Keywords

Links

Crossrefs

Cf. A001047.
Primes p such that k^p - (k-1)^p is composite: this sequence (k=3), A087490 (k=4), A087685 (k=5), A087749 (k=6), A087759 (k=7), A087763 (k=8), A087894 (k=9), A087895 (k=10).

Programs

  • Mathematica
    Select[Prime[Range[100]],CompositeQ[3^#-2^#]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Feb 18 2018 *)
  • PARI
    apmb(a,b,n) = { forprime(x=2,n, y=a^x-b^x; if(!ispseudoprime(y), print1(x","); ) ) }

Extensions

Offset corrected by Mohammed Yaseen, Jul 17 2022

A087490 Primes p such that 4^p - 3^p is composite.

Original entry on oeis.org

5, 11, 13, 19, 23, 29, 31, 37, 41, 43, 47, 53, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 293, 307
Offset: 1

Views

Author

Cino Hilliard, Oct 26 2003

Keywords

Comments

Primes not in A059801. - Robert Israel, Nov 03 2024

Links

Crossrefs

Cf. A005061, A059801.
Primes p such that k^p - (k-1)^p is composite: A087489 (k=3), this sequence (k=4), A087685 (k=5), A087749 (k=6), A087759 (k=7), A087763 (k=8), A087894 (k=9), A087895 (k=10).

Programs

  • Maple
    filter:= p -> isprime(p) and not isprime(4^p-3^p):
select(filter, [seq(i,i=3..1000,2)]); # Robert Israel, Nov 03 2024
  • Mathematica
    Select[Prime[Range[70]],CompositeQ[4^#-3^#]&] (* Harvey P. Dale, Mar 14 2025 *)
  • PARI
    apmb(a,b,n) = { forprime(x=2,n, y=a^x-b^x; if(!ispseudoprime(y), print1(x","); ) ) }

Extensions

Offset corrected by Mohammed Yaseen, Jul 18 2022

A087763 Primes p such that 8^p - 7^p is composite.

Original entry on oeis.org

2, 3, 5, 13, 19, 23, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 83, 89, 97, 101, 103, 107, 109, 127, 137, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317
Offset: 1

Views

Author

Cino Hilliard, Oct 26 2003

Keywords

Crossrefs

Cf. A016177.
Primes p such that k^p - (k-1)^p is composite: A087489 (k=3), A087490 (k=4), A087685 (k=5), A087749 (k=6), A087759 (k=7), this sequence (k=8), A087894 (k=9), A087895 (k=10).

Programs

  • Mathematica
    Select[Prime[Range[70]],CompositeQ[8^#-7^#]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 15 2018 *)
  • PARI
    apmb(a,b,n) = { forprime(x=2,n, y=a^x-b^x; if(!ispseudoprime(y), print1(x","); ) ) }

Extensions

Offset corrected by Mohammed Yaseen, Jul 18 2022

A087894 Primes p such that 9^p - 8^p is composite.

Original entry on oeis.org

3, 5, 11, 13, 17, 19, 23, 37, 41, 43, 47, 53, 59, 61, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307
Offset: 1

Views

Author

Cino Hilliard, Oct 26 2003

Keywords

Crossrefs

Cf. A016185.
Primes p such that k^p - (k-1)^p is composite: A087489 (k=3), A087490 (k=4), A087685 (k=5), A087749 (k=6), A087759 (k=7), A087763 (k=8), this sequence (k=9), A087895 (k=10).

Programs

  • Mathematica
    Select[Prime[Range[100]],!PrimeQ[9^#-8^#]&] (* Harvey P. Dale, May 01 2011 *)
  • PARI
    apmb(a,b,n) = { forprime(x=2,n, y=a^x-b^x; if(!ispseudoprime(y), print1(x","); ) ) }

Extensions

Offset corrected by Mohammed Yaseen, Jul 19 2022

A087895 Primes p such that 10^p - 9^p is composite.

Original entry on oeis.org

5, 13, 17, 23, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293
Offset: 1

Views

Author

Cino Hilliard, Oct 26 2003

Keywords

Crossrefs

Cf. A016189, A062576.
Primes k such that x^k - (x-1)^k is composite: A087489 (x=3), A087490 (x=4), A087685 (x=5), A087749 (x=6), A087759 (x=7), A087763 (x=8), A087894 (x=9), this sequence (x=10).

Programs

  • Mathematica
    Select[Prime[Range[100]],!PrimeQ[10^#-9^#]&] (* Harvey P. Dale, Jun 21 2012 *)
  • PARI
    apmb(a,b,n) = { forprime(x=2,n, y=a^x-b^x; if(!ispseudoprime(y), print1(x","); ) ) }

Extensions

Offset corrected by Mohammed Yaseen, Jul 19 2022
Showing 1-5 of 5 results.

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