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A129822
Array read by rows: each row lists three consecutive nonprime odd numbers.
1
91, 93, 95, 115, 117, 119, 117, 119, 121, 119, 121, 123, 121, 123, 125, 141, 143, 145, 143, 145, 147, 183, 185, 187, 185, 187, 189, 201, 203, 205, 203, 205, 207, 205, 207, 209, 213, 215, 217, 215, 217, 219, 217, 219, 221, 243, 245, 247, 245, 247, 249, 285
OFFSET
1,1
LINKS
MAPLE
a:=proc(n) if isprime(2*n-1)=false and isprime(2*n+1)=false and isprime(2*n+3)=false then 2*n-1, 2*n+1, 2*n+3 else fi end: seq(a(n), n=1..150);
MATHEMATICA
Flatten[Table[If[OddQ[n - 1] && PrimeQ[n - 1] == False && PrimeQ[n + 1] == False && PrimeQ[n + 3] == False, {{n - 1}, {n + 1}, {n + 3}}, {}], {n, 2, 300}]]
Select[Partition[Range[1, 301, 2], 3, 1], NoneTrue[#, PrimeQ]&]//Flatten (* Harvey P. Dale, Jul 16 2021 *)
CROSSREFS
Cf. A099019 (second column), A161945 (first column).
Sequence in context: A043811 A043820 A077685 * A321998 A351624 A020318
KEYWORD
nonn,tabf
AUTHOR
Roger L. Bagula, May 20 2007
EXTENSIONS
Edited by N. J. A. Sloane, Jun 09 2007
Definition modified by Harvey P. Dale, Jul 16 2021
STATUS
approved