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Search: id:A134125
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| A134125 |
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Integral quotients of prime partial sums divided by the running count of summations. |
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+0
6
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| 5, 5, 7, 11, 16, 107, 338, 1011, 2249, 22582, 35989, 39167, 61019, 186504, 248776, 367842, 977511, 1790714, 7104697, 15450640, 42428590
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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With 1 summation, the partial sum is 2+3=5 and 5/1=5 is integer, added to sequence. With 2 summations, the partial sum is 2+3+5=10 and 10/2=5 is integer, added to the sequence. After 3 summations, 2+3+5+7=17 and 17/3=5.6.. is not integer, no contribution to the sequence.
These are all integers of the form a(n)=A007504(k+1)/k, occurring at k=A134126(n). Similar to A050248, which looks at A007504(k)/k. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 23 2007
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EXAMPLE
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a(1)=5 because 2+3=5 and 5/1=5, an integral quotient. a(3)= A007504(5)/4 = 28/4 =7. a(4)=A007504(8)/7 = 77/7 =11.
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PROGRAM
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UBASIC: 10 'primes using counters 20 N=3:C=1:R=5:print 2; 3, 5 30 A=3:S=sqrt(N) 40 B=N\A 50 if B*A=N then N=N+2:goto 30 60 A=A+2:O=A 70 if A<=sqrt(N) then 40 80 C=C+1 90 R=R+N:T=R/C:U=R-N 100 if T=int(T) then print C; U; N; R; T:stop 110 N=N+2:goto 30
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CROSSREFS
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Cf. A134126, A134127, A134128, A134129.
Sequence in context: A120220 A153105 A154583 this_sequence A097996 A033300 A134130
Adjacent sequences: A134122 A134123 A134124 this_sequence A134126 A134127 A134128
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KEYWORD
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more,nonn
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AUTHOR
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Enoch Haga (Enokh(AT)comcast.net), Oct 09 2007
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EXTENSIONS
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a(21) from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 23 2007
Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 17 2009
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