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A096175 Numbers k such that k^3-1 is an odd semiprime. 9
6, 8, 12, 14, 20, 24, 38, 54, 62, 80, 90, 110, 138, 150, 164, 168, 192, 194, 272, 278, 314, 332, 348, 398, 402, 434, 500, 572, 642, 644, 720, 728, 762, 798, 812, 860, 864, 878, 920, 992, 1020, 1022, 1070, 1092, 1098, 1118, 1130, 1182, 1202, 1230, 1260, 1308 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

Dario A. Alpern, Factorization using the Elliptic Curve Method

EXAMPLE

a(1)=6 because 6^3 - 1 = 216 - 1 = 215 = 5*43.

PROG

(PARI)

forstep (k=2, 1310, 2, if(bigomega(k^3-1)==2, print1(k, ", ")))

\\ Hugo Pfoertner, Nov 28 2017

CROSSREFS

Cf. A096173: k^3+1 is an odd semiprime; A081257: largest prime factor of k^3-1; A096176 (k^3-1)/(k-1) is prime; A046315.

Sequence in context: A315858 A123303 A063207 * A274349 A315859 A315860

Adjacent sequences:  A096172 A096173 A096174 * A096176 A096177 A096178

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Jun 22 2004

STATUS

approved

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Last modified December 6 04:43 EST 2019. Contains 329784 sequences. (Running on oeis4.)