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A139081 a(n) = (largest prime power dividing n) + (largest prime power dividing (n+1)). 3

%I #9 Nov 18 2014 08:49:11

%S 3,5,7,9,8,10,15,17,14,16,15,17,20,12,21,33,26,28,24,12,18,34,31,33,

%T 38,40,34,36,34,36,63,43,28,24,16,46,56,32,21,49,48,50,54,20,32,70,63,

%U 65,74,42,30,66,80,38,19,27,48,88,64,66,92,40,73,77,24,78,84,40,30

%N a(n) = (largest prime power dividing n) + (largest prime power dividing (n+1)).

%C The largest prime-power dividing 12 is 4. The largest prime power dividing 13 is 13. So a(12) = 4+13 = 17.

%H Harvey P. Dale, <a href="/A139081/b139081.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A034699(n) + A034699(n+1). [From _Franklin T. Adams-Watters_, Apr 09 2009]

%t With[{c=Table[Max[#[[1]]^#[[2]]&/@FactorInteger[n]],{n,70}]},Total/@ Partition[ c,2,1]] (* _Harvey P. Dale_, Nov 18 2014 *)

%o Contribution from _Franklin T. Adams-Watters_, Apr 09 2009: (Start)

%o (PARI) maxpp(n)=local(m,r,pp);m=factor(n);r=1;for(i=1,matsize(m)[1],pp=m[i,1]^m[i,2];if(pp>r,r=pp));r

%o vector(80,i,maxpp(i)+maxpp(i+1)) (End)

%Y Cf. A139082, A139083.

%K nonn

%O 1,1

%A _Leroy Quet_, Apr 07 2008

%E More terms from _Franklin T. Adams-Watters_, Apr 09 2009

%E Definition clarified by _Harvey P. Dale_, Nov 18 2014

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Last modified April 23 16:40 EDT 2024. Contains 371916 sequences. (Running on oeis4.)