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Search: id:A110208
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| A110208 |
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1 + sum of first n semiprimes. |
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+0
3
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| 1, 5, 11, 20, 30, 44, 59, 80, 102, 127, 153, 186, 220, 255, 293, 332, 378, 427, 478, 533, 590, 648, 710, 775, 844, 918, 995, 1077, 1162, 1248, 1335, 1426, 1519, 1613, 1708, 1814, 1925, 2040, 2158, 2277, 2398, 2520, 2643, 2772, 2905, 3039, 3180, 3322, 3465
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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First differences are the sequence of semiprimes (A001358). Hence a(n) is the least positive sequence whose first differences are the sequence of semiprimes. Primes in this sequence include: a(1) = 5, a(2) = 11, a(6) = 59, a(9) = 127, a(14) = 293, a(33) = 1613. Semiprimes in this sequence include: a(17) = 427 = 7 * 61, a(18) = 478 = 2 * 239, a(19) = 533 = 13 * 41, a(26) = 995 = 5 * 199, a(27) = 1077 = 3 * 359, a(35) = 1814 = 2 * 907, a(42) = 2643 = 3 * 881, a(45) = 3039 = 3 * 1013.
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FORMULA
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a(0) = 1; for n>0, a(n) = 1 + A062198(n).
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CROSSREFS
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Cf. A001358, A062198, A110209, A110226.
Sequence in context: A033913 A088124 A029456 this_sequence A034308 A032527 A026038
Adjacent sequences: A110205 A110206 A110207 this_sequence A110209 A110210 A110211
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), Sep 06 2005
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