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Search: id:A055496
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A055496 a(1) = 2; a(n) is smallest prime > 2*a(n-1). +0
16
2, 5, 11, 23, 47, 97, 197, 397, 797, 1597, 3203, 6421, 12853, 25717, 51437, 102877, 205759, 411527, 823117, 1646237, 3292489, 6584983, 13169977, 26339969, 52679969, 105359939, 210719881, 421439783, 842879579, 1685759167, 3371518343 (list; graph; listen)
OFFSET

1,1

MAPLE

A055496 := proc(n) option remember; if n=1 then 2 else nextprime(2*A055496(n-1)); fi; end;

MATHEMATICA

NextPrim[n_Integer] := Block[ {k = n + 1}, While[ !PrimeQ[k], k++ ]; Return[k]]; a[1] = 2; a[n_] := NextPrim[ 2*a[n - 1]]; Table[ a[n], {n, 1, 31} ]

a[1]=2; a[n_]:=a[n]=Prime[PrimePi[2*a[n-1]]+1]; Table[a[n], {n, 40}] - Zak Seidov (zakseidov(AT)yahoo.com), Feb 16 2006

CROSSREFS

Cf. A006992.

Sequence in context: A055010 A083329 A081973 this_sequence A105120 A084403 A055011

Adjacent sequences: A055493 A055494 A055495 this_sequence A055497 A055498 A055499

KEYWORD

nonn

AUTHOR

njas, Jul 07 2000

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.


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