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A143852
(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 (abs(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
6, 8, 1, 16, 16, 13, 21, 20, 13, 34, 7, 17, 36, 37, 17, 27, 5, 13, 3, 29, 28, 6, 30, 8, 17, 66, 9, 1, 47, 52, 89, 8, 14, 77, 41, 81, 6, 31, 1, 1, 91, 8, 124, 13, 31, 13, 82, 17, 55, 69, 103, 10, 13, 100, 119, 18, 155, 6, 91, 40, 111, 11, 32, 55, 9, 10, 15, 37, 10, 115, 23, 124, 17
OFFSET
1,1
LINKS
EXAMPLE
Abs (2-7-3-5)=abs (-13) =13=a(6).
Abs (2-4-17-2)=abs(-21)=21=a(7).
Abs (3-2-19-2)=abs (-20)=20=a(8).
Abs (2-5-3-7)=abs (-13)=13=a(9).
Abs (2-11-23-2)=abs(-34)=34=a(10),
etc.
MAPLE
g:= proc(n) local F;
F:= sort(ifactors(n)[2], (a, b) -> a[1]<b[1]);
op(subs(1=NULL, map(op, F)));
end proc:
g(1):= 1:
L:= map(g, [$1..300]):
seq(abs(L[i]-L[i+1]-L[i+2]-L[i+3]), i=1..nops(L)-3, 4); # Robert Israel, Apr 25 2016
MATHEMATICA
Abs@ Total@ MapAt[Abs, Minus@ #, {1}] & /@ Partition[#, 4] &@ Flatten[FactorInteger /@ Range@ 134 /. {a_, b_} /; b == 1 :> {a}] (* Michael De Vlieger, Apr 25 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected (10 replaced by 8) and extended by R. J. Mathar, Apr 18 2010
STATUS
approved