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A114520 Composites in sequence A114518. 2
6, 10, 12, 18, 22, 24, 28, 34, 36, 40, 48, 52, 54, 58, 72, 76, 82, 88, 100, 108, 112, 118, 142, 148, 160, 162, 165, 172, 184, 192, 196, 202, 208, 210, 214, 232, 250, 268, 273, 274, 288, 298, 316, 345, 352, 358, 382, 384, 385, 388, 390, 394, 399, 400, 412, 420 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..56.

EXAMPLE

24 is a composite. 24 = 2^3 * 3 and 2^3 + 3 = 11, which is prime. So 24 is in the sequence.

MATHEMATICA

f[n_] := Plus @@ Power @@@ FactorInteger[n]; Select[Select[Range[425], PrimeQ[f[ # ]] &], ! PrimeQ[ # ] &] (* Ray Chandler, Dec 07 2005 *)

PROG

(PARI) A008475(n)=local(t); if(n<1, 0, t=factor(n); sum(k=1, matsize(t)[1], t[k, 1]^t[k, 2])); for(i=1, 700, if(!isprime(i)&&isprime(A008475(i)), print1(i, ", "))) (Herrgesell)

CROSSREFS

Cf. A008475, A114518, A114521, A047820.

Sequence in context: A315126 A315127 A231567 * A315128 A315129 A315130

Adjacent sequences:  A114517 A114518 A114519 * A114521 A114522 A114523

KEYWORD

nonn

AUTHOR

Leroy Quet, Dec 05 2005

EXTENSIONS

Extended by Ray Chandler and Lambert Herrgesell (zero815(AT)googlemail.com), Dec 07 2005

STATUS

approved

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Last modified July 2 18:27 EDT 2022. Contains 355029 sequences. (Running on oeis4.)