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A084334
a(1) = 1; a(n+1) is the least squarefree m not already used such that |m-a(n)| is not equal to |a(k+1)-a(k)| for any k < n.
3
1, 2, 5, 3, 7, 13, 6, 11, 19, 10, 21, 31, 14, 26, 39, 15, 29, 47, 17, 33, 53, 22, 37, 58, 23, 42, 65, 38, 66, 30, 55, 77, 34, 67, 35, 61, 95, 41, 70, 107, 43, 82, 122, 46, 87, 129, 51, 89, 133, 59, 105, 57, 102, 149, 62, 111, 161, 69, 127, 71, 123, 174, 73, 130, 183, 74
OFFSET
1,2
LINKS
MAPLE
N:= 1000: # for terms before the first term > N
A[1]:= 1:
SF:= select(numtheory:-issqrfree, [$2..N]):
DA:= {}:
y:= 1:
found:= true:
for n from 2 while found do
found:= false;
for j from 1 to nops(SF) while not found do
x:= SF[j];
if not member(abs(x-y), DA) then
found:= true;
A[n]:= x;
DA:= DA union {abs(x-y)};
SF:= subsop(j=NULL, SF);
y:= x;
fi
od od:
convert(A, list); # Robert Israel, Feb 22 2024
CROSSREFS
Sequence in context: A309006 A082152 A354688 * A096878 A249162 A134563
KEYWORD
nonn,easy
AUTHOR
Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 18 2003
EXTENSIONS
Edited and extended by David Wasserman, Dec 15 2004
STATUS
approved