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A330410
a(n) = 6*prime(n) - 1.
0
11, 17, 29, 41, 65, 77, 101, 113, 137, 173, 185, 221, 245, 257, 281, 317, 353, 365, 401, 425, 437, 473, 497, 533, 581, 605, 617, 641, 653, 677, 761, 785, 821, 833, 893, 905, 941, 977, 1001, 1037, 1073, 1085, 1145, 1157, 1181, 1193, 1265, 1337, 1361, 1373, 1397, 1433, 1445
OFFSET
1,1
COMMENTS
Composite terms are a(k) with k in {5, 6, 11, 12, 13, 18, 20, 21, ...} = indices of primes missing in A158015. Primes are A016969(A158015 - 1).
FORMULA
a(n) = A016969(A000040(n)-1) = 6p - 1 with p = A000040(n) = prime(n).
PROG
(PARI) apply( a(n)=6*prime(n)-1, [1..99])
(PARI) apply( n->6*n-1, primes(99))
CROSSREFS
Cf. A000040 (primes), A016969 (6n+5), A024898 (6n-1 is prime), A158015 (primes in A024898), A049452 = {n(6n-1)}, A255584 = A033570(A130800) (semiprimes (2n+1)(3n+1)), A245365 (primes of the form n(3n-1)/2).
Sequence in context: A105170 A162175 A178128 * A111255 A060213 A234098
KEYWORD
nonn
AUTHOR
M. F. Hasler, Dec 13 2019
STATUS
approved