

A083119


Sum of n terms from the nth term is a square: a(1), a(2) + a(3), a(3) + a(4) + a(5),..., a(n) + a(n+1) + ...+ a(2n1) are squares.


1



1, 2, 7, 3, 6, 4, 12, 5, 9, 8, 11, 10, 26, 13, 18, 14, 35, 15, 19, 16, 48, 17, 25, 20, 23, 21, 40, 22, 28, 24, 33, 27, 71, 29, 51, 30, 32, 31, 37, 34, 86, 36, 67, 38, 95, 39, 47, 41, 42, 43, 45, 44, 113, 46, 65, 49, 121, 50, 55, 52, 132, 53, 63, 54, 58
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OFFSET

1,2


COMMENTS

a(2n) is the smallest number that has not occurred earlier and a(2n+1) is the smallest number (again not included earlier) required to satisfy the requirement. Another permutation of natural numbers.


LINKS

Table of n, a(n) for n=1..65.


PROG

(GAP) sq := List([1..100], x>x^2); l := [1]; k := 2;
repeat m := Minimum(Difference([1..Size(l)+1], l)); Add(l, m);
sum := Sum(List([k..2*k2], x>l[x]));
m := sq[PositionProperty(sq, x>x>sum and not xsum in l)]sum;
Add(l, m); k := k+1;
until k = 50; l;  Simon Nickerson (simonn(AT)maths.bham.ac.uk), Jun 29 2005


CROSSREFS

Cf. A083121.
Sequence in context: A082737 A104957 A329333 * A246163 A198388 A011304
Adjacent sequences: A083116 A083117 A083118 * A083120 A083121 A083122


KEYWORD

nonn


AUTHOR

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Apr 23 2003


EXTENSIONS

More terms from Simon Nickerson (simonn(AT)maths.bham.ac.uk), Jun 29 2005


STATUS

approved



