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A278021
Numbers n such that n - lambda(n) is prime, where lambda = A002322.
2
4, 9, 15, 25, 33, 35, 49, 65, 69, 77, 87, 91, 95, 115, 119, 121, 123, 143, 159, 169, 185, 187, 215, 221, 247, 249, 255, 259, 267, 287, 289, 295, 299, 319, 323, 329, 339, 341, 361, 365, 377, 393, 395, 407, 413, 415, 427, 437, 455, 473, 485, 511, 515, 519
OFFSET
1,1
COMMENTS
All terms are composite.
4 is the only even term.
For odd primes p, 3*p is a term iff p is in A005384.
LINKS
FORMULA
A010051(n - A002322(n)) = 1.
EXAMPLE
25-lambda(25) = 25-20 = 5 is prime so 25 is in the sequence.
MAPLE
select(t -> isprime(t - numtheory:-lambda(t)), [$1..10000]);
CROSSREFS
Contains A001248. Contained in union of A001248 and A024556.
Sequence in context: A109641 A134675 A050530 * A102084 A193315 A030664
KEYWORD
nonn
AUTHOR
Robert Israel, Nov 08 2016
STATUS
approved