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A144415
Nonprimes of the form (p(n)-2*n)/5, where p(n)=n-th prime.
1
0, 1, 21, 27, 45, 55, 57, 63, 65, 69, 77, 87, 91, 115, 121, 125, 141, 145, 175, 185, 195, 201, 203, 215, 219, 235, 237, 279, 289, 291, 295, 299, 305, 315, 319, 335, 339, 343, 381, 385, 435, 437, 441, 477, 497, 507, 533, 539, 543, 549, 561, 567, 581, 591, 629, 639, 649
OFFSET
1,3
LINKS
EXAMPLE
a(1) = (p(1)-2*1)/5 = (2-2)/5 = 0.
a(2) = (p(9)-2*9)/5 = (23-18)/5 = 1.
MATHEMATICA
Select[Table[(Prime[n]-2n)/5, {n, 1000}], IntegerQ[#]&&!PrimeQ[#]&]//Union (* Harvey P. Dale, Jun 04 2023 *)
CROSSREFS
Sequence in context: A362008 A247316 A072392 * A098898 A098768 A208157
KEYWORD
nonn,easy,less
AUTHOR
EXTENSIONS
Corrected and extended by Charles R Greathouse IV, Mar 26 2010
STATUS
approved