OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
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
Juri-Stepan Gerasimov, Nov 17 2008
EXTENSIONS
Corrected (10 replaced by 8) and extended by R. J. Mathar, Apr 18 2010
STATUS
approved