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A022459 a(n) = prime(2n+1) mod prime(n). 1
1, 2, 2, 2, 9, 2, 13, 2, 21, 15, 21, 23, 21, 23, 33, 31, 31, 35, 33, 37, 45, 39, 45, 49, 39, 39, 51, 55, 59, 57, 53, 51, 57, 69, 55, 65, 65, 63, 67, 73, 73, 77, 67, 75, 73, 89, 77, 63, 69, 89, 97, 93, 105, 97, 93, 91, 93, 101, 99, 99, 111, 105, 95, 105, 113, 117 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A031368(n+1) modulo A000040(n). - Michel Marcus, Sep 30 2013

For n > 8, a(n) = prime(2n+1) - 2*prime(n). - Charles R Greathouse IV, Sep 30 2013

MATHEMATICA

Table[Mod[Prime[2*n + 1], Prime[n]], {n, 100}] (* T. D. Noe, Sep 30 2013 *)

PROG

(PARI) a(n) = prime(2*n+1) % prime(n); \\ Michel Marcus, Sep 30 2013

(PARI) v=vector(100, i, 1); p=2; q=5; for(n=2, #v, q=nextprime(nextprime(q+1) + 1); p=nextprime(p+1); v[n]=q%p); v \\ Charles R Greathouse IV, Sep 30 2013

(MAGMA) [NthPrime(2*n+1) mod NthPrime(n): n in [1..50]]; // G. C. Greubel, Feb 28 2018

CROSSREFS

Sequence in context: A075097 A138056 A340080 * A060804 A086364 A260662

Adjacent sequences:  A022456 A022457 A022458 * A022460 A022461 A022462

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Missing term a(57) inserted by Michel Marcus, Sep 30 2013

STATUS

approved

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Last modified June 15 18:33 EDT 2021. Contains 345049 sequences. (Running on oeis4.)