A168531 - OEIS

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A168531

Numbers that are the products of 3 distinct primes and they are sum of 3 consecutive products of 3 distinct primes.

138, 285, 354, 715, 759, 861, 1158, 1335, 1362, 1390, 1498, 1582, 1767, 1834, 1986, 2013, 2065, 2255, 2298, 2345, 2390, 2406, 2702, 2865, 2967, 3201, 3245, 3302, 3435, 3678, 3730, 3801, 3846, 3874, 3955, 4015, 4053, 4090, 4142, 4498, 4521, 4551, 4634

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..43.

EXAMPLE

30+42+66=138, 78+102+105=285,..

MATHEMATICA

f[n_]:=Last/@FactorInteger[n]=={1, 1, 1}; a=30; b=42; lst={}; Do[If[f[n], p=a+b+n; If[f[p], AppendTo[lst, p]]; a=b; b=n], {n, 65, 7!}]; lst

CROSSREFS

Cf. A007304

Sequence in context: A264897 A202441 A187206 * A260133 A317579 A281592

Adjacent sequences: A168528 A168529 A168530 * A168532 A168533 A168534

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Nov 28 2009

STATUS

approved