A115018 - OEIS

A115018

Numbers k such that (k+1)*(k+2)^2 + 1 is prime.

0, 1, 3, 4, 6, 11, 12, 19, 22, 24, 26, 27, 31, 32, 33, 34, 38, 41, 43, 46, 47, 48, 49, 53, 56, 74, 78, 81, 87, 88, 91, 94, 97, 98, 99, 102, 108, 109, 113, 116, 118, 119, 122, 131, 133, 136, 138, 146, 147, 159, 168, 171, 179, 188, 189, 192, 193, 199

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OFFSET

1,3

COMMENTS

One less than the entry in A154686 at the same index.

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

If k=34 then (k+1)*(k+2)^2 + 1 = 45361 (prime).

MATHEMATICA

Select[Range[0, 200], PrimeQ[(# + 1)*(# + 2)^2 + 1] &] (* Stefan Steinerberger, Mar 02 2006 *)

PROG

(Magma) [ n: n in [0..500] | IsPrime((n+1)*(n+2)^2 + 1) ]; // Vincenzo Librandi, Jan 31 2011

(PARI) is(n)=isprime((n+1)*(n+2)^2+1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A154686.

Sequence in context: A047413 A331191 A294917 * A057030 A230430 A154331

Adjacent sequences: A115015 A115016 A115017 * A115019 A115020 A115021

KEYWORD

nonn,easy

AUTHOR

Parthasarathy Nambi, Feb 23 2006

EXTENSIONS

More terms from Stefan Steinerberger, Mar 02 2006

STATUS

approved