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A189119 Sums s of three consecutive composite odd numbers such that s is also smallest of three consecutive composite odd numbers. 0
621, 867, 891, 897, 1023, 1239, 1413, 1587, 1881, 2091, 2115, 2145, 2169, 2403, 2451, 2505, 2601, 2769, 2871, 2889, 3003, 3129, 3171, 3231, 3237, 3243, 3399, 3417, 3423, 3435, 3441, 3471, 3477, 3501, 3807, 3813, 3933, 3993, 4029 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..39.

EXAMPLE

621 is a smallest of three consecutive odd composite numbers: 621,623,625;

621 is a sum of three consecutive odd composite numbers: 205+207+209=621;

MATHEMATICA

fQ[n_]:=!PrimeQ[n]&&!PrimeQ[n+2]&&!PrimeQ[n+4];

lst1=Select[Range[3, 9000, 2], fQ];

lst2=3*Select[Range[3, 3000, 2], fQ]+6;

Intersection[lst1, lst2]

CROSSREFS

Cf. A002808, A161945.

Sequence in context: A010031 A252527 A232422 * A203086 A251243 A184226

Adjacent sequences:  A189116 A189117 A189118 * A189120 A189121 A189122

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Apr 16 2011

STATUS

approved

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Last modified June 25 12:55 EDT 2019. Contains 324352 sequences. (Running on oeis4.)