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A130593 Evil semiprimes. 4
6, 9, 10, 15, 33, 34, 39, 46, 51, 57, 58, 65, 77, 85, 86, 95, 106, 111, 119, 123, 129, 141, 142, 159, 166, 169, 177, 178, 183, 187, 201, 202, 209, 215, 219, 221, 226, 235, 237, 249, 267 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Products of two (not necessarily distinct) primes such that the product has an even number of 1's in its binary expansion. Non-evil semiprimes are odious (A000069).

REFERENCES

Fouvry, E.; Mauduit, C. Sommes des chiffres et nombres presque premiers. (French) [Sums of digits and almost primes] Math. Ann. 305 (1996), no. 3, 571--599. MR1397437 (97k:11029)

LINKS

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

FORMULA

A001358 INTERSECTION A001969.

MATHEMATICA

Select[Range[300], PrimeOmega[#]==2&&EvenQ[DigitCount[#, 2, 1]]&] (* Harvey P. Dale, Nov 08 2011 *)

PROG

(PARI) list(lim)=my(v=List(), t); forprime(p=2, lim\2, forprime(q=2, min(p, lim\p), if(hammingweight(n=p*q)%2, , listput(v, n)))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Mar 26 2013

CROSSREFS

Cf. A000069, A001358, A001969.

Sequence in context: A020219 A175634 A134622 * A051221 A029843 A209941

Adjacent sequences:  A130590 A130591 A130592 * A130594 A130595 A130596

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Jun 16 2007

EXTENSIONS

Corrected (a(21)=129 added) by Harvey P. Dale, Nov 08 2011

STATUS

approved

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Last modified August 21 17:52 EDT 2017. Contains 290892 sequences.