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Search: id:A058849
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%I A058849
%S A058849 9,55,99,215,357,663,3725,6321,26999,191363,675861,4073533,4180943,
%T A058849 5540147,6531789,400974175,4248550291,6224149881,17109266357
%N A058849 Sum of odd composites up to n is palindromic.
%C A058849 Sequence is 9 + 15 + 21 + 25 + 27 + 33 + ... + n.
%H A058849 P. De Geest, <a href="http://www.worldofnumbers.com/firstpal.htm#sfn4">
               Palindromic Sums</a>
%F A058849 sum[A071904(i),i=1..j]=A002113(k) for A071904(j)=n and some k. - R. J. 
               Mathar (mathar(AT)strw.leidenuniv.nl), Jan 29 2007
%p A058849 nextA071904 := proc(n) local a ; a := n + 2 - ((n+1) mod 2); while isprime(a) 
               do a := a+2 ; od ; RETURN(a) ; end: isA002113 := proc(n) local drev,
               i ; drev := convert(n,base,10) ; for i from 1 to nops(drev)/2 do 
               if op(i,drev) <> op(-i,drev) then RETURN(false) ; fi ; od ; RETURN(true) 
               ; end: nextA058844 := proc(n,nsum) local a, asum ; a := nextA071904(n) 
               ; asum := nsum+a ; while not isA002113(asum) do a := nextA071904(a) 
               ; asum := asum+a ; od ; RETURN([a, asum]) ; end: n := 9 ; nsum := 
               9 ; nnsum := [n,nsum] ; for i from 1 to 40 do print(op(1,nnsum)) 
               ; nnsum := nextA058844(op(1,nnsum),op(2,nnsum)) ; od : - R. J. Mathar 
               (mathar(AT)strw.leidenuniv.nl), Jan 29 2007
%Y A058849 Cf. A058848, A058850.
%Y A058849 Sequence in context: A157546 A157560 A157588 this_sequence A058852 A145875 
               A068970
%Y A058849 Adjacent sequences: A058846 A058847 A058848 this_sequence A058850 A058851 
               A058852
%K A058849 nonn,base,more
%O A058849 1,1
%A A058849 Patrick De Geest (pdg(AT)worldofnumbers.com), Dec 15 2000.

    
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Last modified December 13 23:45 EST 2009. Contains 170824 sequences.


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