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A086046
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Sum of first n 4-almost primes.
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5
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16, 40, 76, 116, 170, 226, 286, 367, 451, 539, 629, 729, 833, 959, 1091, 1226, 1362, 1502, 1652, 1804, 1960, 2144, 2333, 2529, 2727, 2931, 3141, 3361, 3586, 3814, 4046, 4280, 4528, 4778, 5038, 5314, 5608, 5904, 6201, 6507, 6815, 7130, 7458, 7788, 8128
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Elements in this sequence can themselves be 4-almost primes. a(1) = 16 = 2^4. a(2) = 40 = 2^3 * 5. a(19) = 1652 = 2^2 * 7 * 59. a(20) = 1804 = 2^2 * 11 * 41. a(31) = 4046 = 2 * 7 * 17^2. a(37) = 5608 = 2^3 * 701. a(39) = 6201 = 3^2 * 13 * 53. a(40) = 6507 = 3^3 * 241. a(42) = 7130 = 2 * 5 * 23 * 31. a(43) = 7458 = 2 * 3 * 11 * 113. Does this happen infinitely often? - Jonathan Vos Post (jvospost3(AT)gmail.com), Dec 11 2004
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EXAMPLE
| a(2)=40 because sum of first two 4-almost primes i.e. 16+24 is 40.
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CROSSREFS
| Sequence in context: A132161 A177723 A174321 * A184030 A205065 A185790
Adjacent sequences: A086043 A086044 A086045 * A086047 A086048 A086049
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KEYWORD
| easy,nonn
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AUTHOR
| Shyam Sunder Gupta (guptass(AT)rediffmail.com), Aug 24 2003
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