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A175461 Semiprimes of form 8n+5. 7
21, 69, 77, 85, 93, 133, 141, 205, 213, 221, 237, 253, 301, 309, 341, 365, 381, 413, 437, 445, 453, 469, 485, 493, 501, 517, 533, 565, 573, 581, 589, 597, 629, 669, 685, 717, 749, 781, 789, 813, 869, 893, 901, 917, 933, 949, 965, 973, 989, 1037, 1077, 1101 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There are no squares of form 8n+5.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[8*Range[200]+5, PrimeOmega[#]==2&] (* Harvey P. Dale, Apr 29 2015 *)

PROG

(PARI) lista(nn) = {vec = vector(nn, i, 8*i+5); smp = select(i->(bigomega(i) == 2), vec); print(smp); } \\ Michel Marcus, Oct 15 2013

CROSSREFS

Cf. A001358 Semiprimes: products of two primes, A004770 Numbers of form 8n+5, A007521 Primes of form 8n+5, A175462 Number of divisors of integers of form 8n+5, A175463 Numbers n such that 8*n+5 is semiprime.

Sequence in context: A123839 A180758 A197121 * A272627 A043339 A023712

Adjacent sequences:  A175458 A175459 A175460 * A175462 A175463 A175464

KEYWORD

nonn

AUTHOR

Zak Seidov, May 23 2010

STATUS

approved

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Last modified July 17 20:45 EDT 2019. Contains 325109 sequences. (Running on oeis4.)