A114520 - OEIS

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A114520

Composites in sequence A114518.

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

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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