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A305709 Least k such that there exists a three-term sequence n = b_1 < b_2 < b_3 = k such that b_1 * b_2 * b_3 is square. 1
8, 6, 8, 16, 10, 12, 14, 18, 25, 20, 22, 20, 26, 24, 27, 32, 34, 27, 38, 30, 28, 33, 46, 32, 48, 52, 40, 45, 58, 42, 62, 45, 48, 54, 56, 64, 74, 57, 52, 50, 82, 56, 86, 55, 60, 69, 94, 54, 72, 63, 75, 78, 106, 75, 90, 72, 76, 96, 118, 80, 122, 96, 84, 98, 104 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) >= A006255(n), and a(n) = A006255(n) if and only if A066400(n) = 3.

Conjecture: a(n) < A072905(n) with finitely many nonsquare exceptions.

LINKS

Peter Kagey, Table of n, a(n) for n = 1..10000

EXAMPLE

For n = 3 the sequence is 3, 6, 8; so a(3) = 8;

for n = 4 the sequence is 4, 9, 16; so a(4) = 16;

for n = 5 the sequence is 5, 8, 10; so a(5) = 10.

CROSSREFS

Cf. A006255, A066400, A072905.

Sequence in context: A246768 A088541 A110214 * A093721 A091506 A021539

Adjacent sequences:  A305706 A305707 A305708 * A305710 A305711 A305712

KEYWORD

nonn

AUTHOR

Peter Kagey, Jun 08 2018

STATUS

approved

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Last modified July 24 11:17 EDT 2021. Contains 346273 sequences. (Running on oeis4.)