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Search: id:A131693
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| A131693 |
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Numbers n such that S(n) = 0, where S(n) = (S(n-1) + A000040(n+1))*(-1)^n; S(0)=0, n=>1. |
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+0
1
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| 10, 14, 18, 4290, 4392, 4434, 4440, 4456, 4480, 48596, 48620, 48744, 49540, 49544, 49722, 55058, 55078, 55200, 56466, 56474, 60110, 60128, 60462, 60750, 61328, 61486, 62114, 62758, 62770, 62974, 62992, 63022, 63076, 63094, 63272, 63802
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Or, with A065091(odd primes), numbers n such that S(n) = 0, where S(n) = (S(n-1) + A065091(n))*(-1)^n; S(0)=0, n=>1.
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EXAMPLE
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S(9)=(..((0+3)*-1)+5)*1)+7)*-1)+11)*1)+13)*-1)+17)*1)+19)*-1)+23)*1)+29)*-1 = -31, S(10)=(-31 + 31)*1 = 0, hence 10 is a term.
S(13)=(..((0+3)*-1)+5)*1)+7)*-1)+11)*1)+13)*-1)+17)*1)+19)*-1)+23)*1)+29)*-1)+31)*1)+37)*-1)+41)*1)+43)*-1 = -47, S(14)=(-47 + 47)*1 = 0, hence 14 is a term.
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MATHEMATICA
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S=0; a=0; Do[S=(S+Prime[n+1])*(-1)^n; If[S==0, a++; Print[a, " ", n]], {n, 1, 10^8, 1}]
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CROSSREFS
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Cf. A131196, A131197, A130642, A130643, A065091, A000040.
Sequence in context: A096851 A121893 A055985 this_sequence A069900 A073492 A073493
Adjacent sequences: A131690 A131691 A131692 this_sequence A131694 A131695 A131696
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KEYWORD
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nonn
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AUTHOR
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Manuel Valdivia (mvaldivia(AT)ugr.es), Oct 03 2007
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