

A243222


Primes p such that p^3  2 and p^2  2 are both semiprimes.


1



11, 17, 41, 79, 199, 307, 331, 349, 379, 613, 643, 661, 673, 701, 769, 877, 883, 947, 1049, 1249, 1279, 1301, 1319, 1381, 1423, 1483, 1543, 1559, 1609, 1667, 1699, 1759, 1777, 1801, 1831, 1871, 1993, 2011, 2083, 2347, 2539, 2621, 2671, 2687, 2777, 2833, 2861
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OFFSET

1,1


COMMENTS

Similar sequence for primes is A242979.
Intersection of A241716 and A242260.


LINKS

K. D. Bajpai, Table of n, a(n) for n = 1..10000


EXAMPLE

11 is prime and appears in the sequence because [ 11^3  2 = 1329 = 3 * 443 ] and [ 11^2  2 = 119 = 7 * 17 ] are both semiprimes.
17 is prime and appears in the sequence because [ 17^3  2 = 4911 = 3 * 1637 ] and [ 17^2  2 = 287 = 7 * 41 ] are both semiprimes.


MAPLE

with(numtheory): A243222:= proc() local p; p:=ithprime(n); if bigomega(p^32)=2 and bigomega(p^22) =2 then RETURN (p); fi; end: seq( A 243222 (), n=1..1000);


MATHEMATICA

A243222 = {}; Do[t = Prime[n]; If[PrimeOmega[t^3  2] == 2 && PrimeOmega[t^2  2] == 2, AppendTo[A243222, t]], {n, 1000}]; A243222


PROG

(PARI) s=[]; forprime(p=2, 3000, if(bigomega(p^22)==2 && bigomega(p^32)==2, s=concat(s, p))); s \\ Colin Barker, Jun 03 2014


CROSSREFS

Cf. A000040, A001358, A062326, A241716, A242260, A241732, A178251, A242979.
Sequence in context: A267291 A073649 A178070 * A090609 A187057 A187058
Adjacent sequences: A243219 A243220 A243221 * A243223 A243224 A243225


KEYWORD

nonn


AUTHOR

K. D. Bajpai, Jun 01 2014


STATUS

approved



