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A225712 Composite squarefree numbers n such that p(i)+2 divides n-2, where p(i) are the prime factors of n. 3
182, 21827, 32942, 46055, 84502, 151202, 191522, 361802, 532247, 780626, 1368642, 1398377, 1425230, 1556258, 1751927, 1932338, 2209727, 3496502, 4078802, 4216862, 4438709, 5191562, 5991477, 7413002, 8385365, 8797502, 11749127, 13634138, 15921677, 16772177 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

Prime factors of 151202 are 2, 19, 23 and 173. We have that (151202-2)/(2+2) = 37800, (151202-2)/(19+2) = 7200, (151202-2)/(23+2) = 6048 and (151202-2)/(173+2)= 864.

MAPLE

with(numtheory); A225712:=proc(i, j) local c, d, n, ok, p, t;

for n from 2 to i do if not isprime(n) then p:=ifactors(n)[2]; ok:=1;

for d from 1 to nops(p) do if p[d][2]>1 or p[d][1]=j then ok:=0; break; fi;

if  not type((n+j)/(p[d][1]-j), integer) then ok:=0; break; fi; od;

if ok=1 then print(n); fi; fi; od; end: A225712(10^9, -2);

MATHEMATICA

t = {}; n = 0; len = -2; While[len <= 262, n++; {p, e} = Transpose[FactorInteger[n]]; If[Length[p] > 1 && Union[e] == {1} && Union[Mod[n - 2, p + 2]] == {0}, AppendTo[t, n]; len = len + Length[IntegerDigits[n]] + 2]]; t (* T. D. Noe, May 17 2013 *)

CROSSREFS

Cf. A208728, A225702-A225711, A225713-A225720.

Sequence in context: A023904 A035839 A048546 * A015306 A190830 A145525

Adjacent sequences:  A225709 A225710 A225711 * A225713 A225714 A225715

KEYWORD

nonn

AUTHOR

Paolo P. Lava, May 13 2013

STATUS

approved

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Last modified August 15 14:58 EDT 2020. Contains 336504 sequences. (Running on oeis4.)