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Search: id:A077133
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| A077133 |
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Difference between the sum of odd indexed primes and even indexed primes. |
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+0
2
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| 1, 3, 5, 7, 13, 19, 21, 27, 29, 33, 39, 45, 49, 53, 57, 61, 63, 65, 71, 77, 79, 81, 83, 95, 97, 103, 113, 119, 121, 125, 135, 139, 143, 149, 151, 157, 163, 167, 175, 183, 185, 187, 191, 199, 201, 213, 217, 221, 233, 251, 261, 267, 273, 279, 281, 287, 289, 299
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Some odd numbers such as 11, 17, 23 and 25 never appear.
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FORMULA
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a(n) = Sum_{i=0..n-1} (p(2i+2)-p(2i+1)).
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EXAMPLE
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a(2)=3 as a_o(2)=10 and a_e(2)=7
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MATHEMATICA
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Table[ Sum[ Prime[2i], {i, 1, n}] - Sum[ Prime[2i - 1], {i, 1, n}], {n, 1, 60}]
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PROGRAM
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(PARI) pc=1; p1s=0; p2s=0; forprime (p=2, 500, pc=3-pc; if (pc==1, p1s=p1s+p, p2s=p2s+p); if (pc==1, print1(p1s-p2s", ")))
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CROSSREFS
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Sequence in context: A106878 A079481 A075571 this_sequence A164642 A120460 A127459
Adjacent sequences: A077130 A077131 A077132 this_sequence A077134 A077135 A077136
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KEYWORD
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nonn
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AUTHOR
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Jon Perry (perry(AT)globalnet.co.uk), Nov 29 2002
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 30 2002
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