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(1, 2, 3, 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 2^2*3, 13, 2*7, 3*5, ...) becomes ((1+2)*3, (2+2)*5, (2+3)*7, (2+3)*3, (2+2)*5, (11+2)*2, (3+13)*2, (7+3)*5, ...).
1

%I #10 Nov 17 2019 01:28:22

%S 9,20,35,15,20,26,32,50,102,10,42,56,299,15,14,48,28,93,72,88,95,18,

%T 185,63,45,92,430,44,25,1175,18,18,21,38,132,30,39,190,1829,12,132,68,

%U 54,36,938,68,52,852,15,150,200,8,286,65,324,32,3569,12,204,135,93,200,25,40

%N (1, 2, 3, 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 2^2*3, 13, 2*7, 3*5, ...) becomes ((1+2)*3, (2+2)*5, (2+3)*7, (2+3)*3, (2+2)*5, (11+2)*2, (3+13)*2, (7+3)*5, ...).

%H Robert Israel, <a href="/A143704/b143704.txt">Table of n, a(n) for n = 1..10000</a>

%e a(8) = ( 7 + 3) * 5 = 10*5 = 50;

%e a(9) = ( 2 + 4) * 17 = 102;

%e a(10) = ( 2 + 3) * 2 = 10;

%e a(11) = (19 + 2) * 2 = 42;

%e a(12) = ( 5 + 3) * 7 = 56;

%e a(13) = ( 2 + 11) * 23 = 199;

%e etc.

%p g:= proc(n) local L; L:= sort(ifactors(n)[2],(s,t) -> s[1]<t[1]);

%p L:= map(proc(t) if t[2]=1 then t[1] else op(t) fi end proc, L);

%p op(L);

%p end proc:

%p g(1):= 1:

%p B:= map(g, [$1..100]):

%p seq((B[3*i+1]+B[3*i+2])*B[3*i+3], i=0..(nops(B)-3)/3); # _Robert Israel_, Nov 16 2019

%Y Cf. A141287, A141261, A136735.

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, Nov 13 2008

%E Corrected (199 replaced by 299, 60 replaced by 30, 549 replaced by 54 etc.) by _R. J. Mathar_, Apr 18 2010