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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Klaus Brockhaus, Table of n, a(n) for n = 1..4948

Eric Weisstein's World of Mathematics, B2-Sequence

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

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Last modified November 19 03:27 EST 2019. Contains 329310 sequences. (Running on oeis4.)