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A116039
Numbers k such that k + prime(k) + prime(prime(k)) is a semiprime (A001358).
2
1, 2, 8, 9, 11, 12, 18, 19, 22, 23, 26, 29, 33, 35, 43, 47, 50, 53, 57, 59, 61, 69, 75, 76, 77, 78, 81, 89, 103, 105, 109, 112, 124, 125, 131, 135, 140, 141, 142, 143, 146, 151, 153, 155, 160, 166, 170, 175, 176, 177, 181, 189, 209, 211, 215, 216, 220, 225, 226
OFFSET
1,2
LINKS
EXAMPLE
112 is in the sequence since 112 + prime(112) + prime(prime(112)) = 5242 = 2*2621.
MAPLE
with(numtheory): A116039:=n->`if`(bigomega(n+ithprime(n)+ithprime(ithprime(n))) = 2, n, NULL): seq(A116039(n), n=1..500); # Wesley Ivan Hurt, Jun 23 2015
CROSSREFS
Sequence in context: A019511 A103190 A345019 * A030334 A338807 A020676
KEYWORD
nonn
AUTHOR
Giovanni Resta, Feb 13 2006
STATUS
approved