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A121615
Lexicographically earliest sequence such that the k-th prime occurs altogether not more than k times as prime factor.
2
2, 3, 5, 7, 11, 13, 15, 17, 19, 23, 29, 31, 35, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 143, 149, 151, 157, 163, 167, 169, 173, 179, 181, 187, 191, 193, 197, 199, 211, 221, 223, 227, 229, 233, 239
OFFSET
1,1
COMMENTS
Subsequence of A037143: 1 <= A001222(a(n)) <= 2; A000040 is a subsequence.
LINKS
EXAMPLE
k=1, prime(1)=2: {2} = {a(1)},
k=2, prime(2)=3: {3,3*5} = {a(2),a(7)},
k=3, prime(3)=5: {5,3*5,5*7} = {a(3),a(7),a(13)},
k=4, prime(4)=7: {7,5*7,7*7} = {a(4),a(7),a(18)},
k=5, prime(5)=11: {11,11*11,11*13,11*17} = {a(5),a(34),a(39),a(49)},
k=6, prime(6)=13: {13,11*13,13*13,13*17,13*19} = {a(6),a(39),a(45),a(55),a(62)};
k=7, prime(7)=17: {17,11*17,13*17,17*17,17*19,17*23} = {a(8),a(49),a(55),a(71),a(77),a(90)}.
CROSSREFS
Sequence in context: A003277 A322833 A117287 * A097605 A143578 A187731
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Aug 11 2006
STATUS
approved