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 1-3 of 3 results.

A023296 Primes that remain prime through 3 iterations of function f(x) = 9x + 2.

Original entry on oeis.org

19, 103, 113, 151, 239, 283, 313, 599, 929, 1481, 2411, 2549, 2593, 2741, 2819, 2969, 3931, 4091, 4463, 4523, 5279, 5923, 6781, 7759, 8209, 8363, 9749, 10133, 10531, 12919, 14071, 15053, 15361, 16229, 16453, 16493, 16573, 16703, 17041, 17783, 18253
Offset: 1

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Author

Keywords

Comments

Primes p such that 9*p+2, 81*p+20 and 729*p+182 are also primes. - Vincenzo Librandi, Aug 04 2010

Crossrefs

Subsequence of A023233 and A023265.

Programs

  • Magma
    [n: n in [1..450000] | IsPrime(n) and IsPrime(9*n+2) and IsPrime(81*n+20) and IsPrime(729*n+182)]; // Vincenzo Librandi, Aug 04 2010
  • Maple
    A023296:=n->`if`(isprime(n) and isprime(9*n+2) and isprime(81*n+20) and isprime(729*n+182), n, NULL): seq(A023296(n), n=1..5*10^4); # Wesley Ivan Hurt, Feb 22 2017
  • Mathematica
    Select[Prime@ Range@ 2100, Times @@ Boole@ PrimeQ@ NestList[9 # + 2 &, #, 3] > 0 &] (* Michael De Vlieger, Feb 22 2017 *)
    Select[Prime[Range[2100]],AllTrue[Rest[NestList[9#+2&,#,3]],PrimeQ]&] (* Harvey P. Dale, May 14 2024 *)

A086154 a(n) = binomial(3^n,2^n).

Original entry on oeis.org

1, 3, 126, 2220075, 33594090947249085, 9812294412288780842726471233974791140221, 747581321238203931168470352555568799370148397202082975882483140118428447896681620077224288595
Offset: 0

Views

Author

Labos Elemer, Aug 07 2003

Keywords

Comments

Upper bound on the number of compressed (irredundant) disjunctive normal forms of Boolean functions with n variables.

References

  • G. P. Gavrilov and A. A. Saposhenko, Problems Book in Discrete Mathematics (Hungarian translation), Muszaki Kiado, 1981.

Crossrefs

Cf. A023265.

Programs

A023352 Primes that remain prime through 5 iterations of function f(x) = 9x + 2.

Original entry on oeis.org

103, 283, 929, 3931, 7759, 52973, 75853, 90031, 93371, 103561, 106949, 110821, 128111, 130841, 137273, 163861, 198553, 288023, 342389, 357031, 377231, 425681, 429973, 435181, 450311, 490663, 526159, 532199, 552791, 574801, 585733, 599719
Offset: 1

Views

Author

Keywords

Comments

Primes p such that 9*p+2, 81*p+20, 729*p+182, 6561*p+1640 and 59049*p+14762 are also primes. - Vincenzo Librandi, Aug 05 2010

Crossrefs

Subsequence of A023233, A023265, A023296, and A023324.

Programs

  • Magma
    [n: n in [1..19000000] | IsPrime(n) and IsPrime(9*n+2) and IsPrime(81*n+20) and IsPrime(729*n+182) and IsPrime(6561*n+1640) and IsPrime(59049*n+14762)] // Vincenzo Librandi, Aug 05 2010
  • Mathematica
    Select[Prime[Range[50000]],AllTrue[Rest[NestList[9#+2&,#,5]],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 24 2017 *)
Showing 1-3 of 3 results.