

A133743


a(n) is the smallest positive square such that pairwise sums of distinct elements are all distinct.


4



1, 4, 9, 16, 25, 36, 49, 100, 144, 169, 225, 256, 361, 441, 484, 625, 729, 784, 1156, 1521, 1600, 1764, 2401, 2704, 3364, 4096, 4225, 4356, 4900, 5184, 5929, 6889, 7921, 8836, 9216, 9409, 10404, 11881, 13689, 13924, 14161, 18496, 19321, 20449, 21316
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OFFSET

1,2


LINKS

Klaus Brockhaus, Table of n, a(n) for n = 1..4948
Eric Weisstein's World of Mathematics, B2Sequence
Index entries for B_2 sequences


EXAMPLE

49 is in the sequence since the pairwise sums of distinct elements of {1, 4, 9, 16, 25, 36, 49} are all distinct: 5, 10, 13, 17, 20, 25, 26, 29, 34, 37, 40, 41, 45, 50, 52, 53, 58, 61, 65, 74, 85.
64 is not in the sequence since 1 + 64 = 16 + 49.


CROSSREFS

Cf. A000290, A062295, A133744, A133745.
Sequence in context: A030288 A030154 A122541 * A235484 A028820 A122683
Adjacent sequences: A133740 A133741 A133742 * A133744 A133745 A133746


KEYWORD

nonn


AUTHOR

Klaus Brockhaus, Sep 24 2007


STATUS

approved



