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A137473 Positive numbers k such that k^3 +- (k-1)^2 are primes. 0
3, 6, 7, 13, 21, 73, 75, 90, 91, 97, 106, 115, 157, 201, 208, 238, 291, 300, 315, 358, 385, 405, 420, 460, 505, 523, 540, 651, 658, 798, 810, 825, 927, 942, 1000, 1105, 1125, 1135, 1186, 1197, 1278, 1315, 1365, 1378, 1380, 1410, 1417, 1476, 1480, 1483, 1557 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..51.

EXAMPLE

3^3 +- 2^2 -> (23, 31) (both primes);

7^3 +- 6^2 -> (307, 379) (both primes).

MATHEMATICA

Select[Range[900], PrimeQ[ #^3-(#-1)^2]&&PrimeQ[ #^3+(#-1)^2]&]

PROG

(MAGMA) [n: n in [0..500] | IsPrime(n^3-(n-1)^2)and IsPrime(n^3 +(n-1)^2)] // Vincenzo Librandi, Nov 24 2010

CROSSREFS

Sequence in context: A124132 A064291 A245394 * A303604 A255683 A127307

Adjacent sequences:  A137470 A137471 A137472 * A137474 A137475 A137476

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Apr 21 2008

EXTENSIONS

More terms from Vincenzo Librandi, Mar 26 2010

STATUS

approved

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Last modified November 15 09:36 EST 2018. Contains 317232 sequences. (Running on oeis4.)