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Search: id:A131610
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| A131610 |
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Semiprimes that are the sum of three successive semiprimes. |
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| 25, 33, 39, 58, 93, 123, 134, 146, 155, 177, 185, 253, 278, 295, 358, 362, 417, 446, 478, 538, 566, 597, 614, 698, 749, 766, 794, 898, 917, 982, 998, 1042, 1059, 1081, 1149, 1159, 1286, 1351, 1393, 1441, 1546, 1589, 1623, 1639, 1649, 1658, 1718, 1766, 1799
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OFFSET
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1,1
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COMMENT
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a(n)=A001358(m)=A001358(i)+A001358(i+1)+A001358(i+2), for some m, i. Corresponding values of m and i are: 9, 11, 15, 21, 32, 42, 45, 50, 51, 57, 60, 81, 88, 92, 113, 115, 132, 137, 147, 168, 178, 186, 188; 2, 3, 4, 6, 10, 14, 15, 16, 17, 20, 21, 27, 31, 33, 38, 39, 45, 49, 52, 57, 60, 62, 65.
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FORMULA
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a(n)=A001358(m)=A001358(i)+A001358(i+1)+A001358(i+2), for some m, i.
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EXAMPLE
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25=6+9+10, or A001358(9)=A001358(2)+A001358(3)+A001358(4),
33=9+10+14, or A001358(11)=A001358(3)+A001358(4)+A001358(5).
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CROSSREFS
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Cf. A001358, A092192.
Sequence in context: A035140 A050694 A107608 this_sequence A134099 A129074 A068411
Adjacent sequences: A131607 A131608 A131609 this_sequence A131611 A131612 A131613
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Oct 02 2007
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