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A225716 Composite squarefree numbers n such that p(i)+6 divides n-6, where p(i) are the prime factors of n. 3
6, 26781, 120791, 5099531, 5720435, 14637451, 24110358, 31552261, 33792198, 57804181, 71925054, 88324781, 92849126, 441031331, 650715071, 924029951, 1425902869, 2093676486, 2336689491, 3273172441, 4533042611, 4711366831, 5162021871, 5502040431, 6427899582 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

Prime factors of 14637451 are 41, 229 and 1559. We have that (14637451-6)/(41+6) = 311435, (14637451-6)/(229+6) = 62287 and (14637451-6)/(1559+6) = 9353.

MAPLE

with(numtheory); A225716:=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: A225716(10^9, -6);

CROSSREFS

Cf. A208728, A225702-A225715, A225717-A225720.

Sequence in context: A283887 A241650 A143780 * A159429 A283888 A134728

Adjacent sequences:  A225713 A225714 A225715 * A225717 A225718 A225719

KEYWORD

nonn

AUTHOR

Paolo P. Lava, May 13 2013

EXTENSIONS

a(14)-a(25) from Donovan Johnson, Nov 15 2013

STATUS

approved

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Last modified February 22 17:14 EST 2020. Contains 332140 sequences. (Running on oeis4.)