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Search: id:A086047
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| A086047 |
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Sum of first n 5-almost primes. |
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+0
4
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| 32, 80, 152, 232, 340, 452, 572, 734, 902, 1078, 1258, 1458, 1666, 1909, 2161, 2425, 2695, 2967, 3247, 3547, 3851, 4163, 4531, 4909, 5301, 5697, 6102, 6510, 6930, 7370, 7820, 8276, 8740, 9208, 9704, 10204, 10724, 11276, 11843, 12431, 13023, 13617
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Elements in this sequence can themselves be 5-almost primes. a(1) = 32 = 2^5. a(2) = 80 = 2^4 * 5. a(27) = 6102 = 2 * 3^3 * 113 a(28) = 6510 = 2 * 3 * 5 * 7 * 31 a(31) = 7820 = 2^2 * 5 * 17 * 23 a(33) = 8740 = 2^2 * 5 * 19 * 23. Does this happen infinitely often? - Jonathan Vos Post (jvospost3(AT)gmail.com), Dec 11 2004
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EXAMPLE
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a(2)=80 because sum of first two 5-almost primes, i.e. 32+48, is 80.
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CROSSREFS
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Sequence in context: A110230 A007797 A135269 this_sequence A043410 A044170 A044551
Adjacent sequences: A086044 A086045 A086046 this_sequence A086048 A086049 A086050
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KEYWORD
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easy,nonn
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AUTHOR
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Shyam Sunder Gupta (guptass(AT)rediffmail.com), Aug 24 2003
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