A175461 Semiprimes of form 8n+5.

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

Offset: 1

Author

Zak Seidov, May 23 2010

Keywords

• nonn

Comments

There are no squares of form 8n+5.

Links

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

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.

Programs

Mathematica

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

PARI

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