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A076274
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2p-1 where p is 1 or a prime.
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28
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1, 3, 5, 9, 13, 21, 25, 33, 37, 45, 57, 61, 73, 81, 85, 93, 105, 117, 121, 133, 141, 145, 157, 165, 177, 193, 201, 205, 213, 217, 225, 253, 261, 273, 277, 297, 301, 313, 325, 333, 345, 357, 361, 381, 385, 393, 397, 421, 445, 453, 457, 465, 477, 481, 501, 513, 525, 537, 541
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OFFSET
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1,2
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 1..1000
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FORMULA
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A076271(a(n)) = A008578(n)^2 for all n.
a(n+1) - a(n) = 2*A075526(n) for all n.
G.f.: 1 + Sum_{ j>=1 } Sum_{ k>=1 } x^(pi(k/2)+j), where pi(k) is the prime counting function. - Benedict W. J. Irwin, Jun 13 2016
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MATHEMATICA
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Join[{1}, 2*Prime[Range[100]]-1] (* Harvey P. Dale, Nov 29 2015 *)
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PROG
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(PARI) a(n)=if(n>1, 2*prime(n-1)-1, 1) \\ Charles R Greathouse IV, Apr 29 2015
(Magma) [2*NthPrime(n-1)-1: n in [1..60]]; // Vincenzo Librandi, Jul 31 2017
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CROSSREFS
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Positions of squares in A076271.
Subsequence of A186621 and of A005408.
Cf. A000010, A002033.
Sequence in context: A007042 A178415 A249424 * A058989 A049691 A206297
Adjacent sequences: A076271 A076272 A076273 * A076275 A076276 A076277
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KEYWORD
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nonn,easy
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AUTHOR
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Reinhard Zumkeller, Oct 04 2002
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EXTENSIONS
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New definition from Thomas Baruchel, Oct 21 2003
Offset changed from Vincenzo Librandi, Jul 31 2017
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STATUS
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approved
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