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A020340

Least square base n doublet (written in base 10).

36, 4, 378225, 7056, 14393520729, 16, 9, 557904400, 1322314049613223140496, 36, 613401598811409576100, 321418490709904, 837225, 16, 7535664872989640713426833504575377836025, 36, 16900, 100, 7112889

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OFFSET

2,1

COMMENTS

In Bridy et al. it is shown how to construct infinitely many examples for any given base n >= 2. - Jeffrey Shallit, Jun 14 2021

REFERENCES

Andrew Bridy, Robert J. Lemke Oliver, Arlo Shallit, and Jeffrey Shallit, The Generalized Nagell-Ljunggren Problem: Powers with Repetitive Representations, Experimental Math, 28 (2019), 428-439.

David Wells, "The Penguin Dictionary of Curious and Interesting Numbers", Revised Edition 1997, p. 189.

LINKS

Table of n, a(n) for n=2..20.

Andrew Bridy, Robert J. Lemke Oliver, Arlo Shallit, and Jeffrey Shallit, The Generalized Nagell-Ljunggren Problem: Powers with Repetitive Representations, preprint arXiv:1707.03894 [math.NT], July 14 2017.

A. Ottens, The arithmetic-digits-squares-three.digits problem

CROSSREFS

Cf. A020339, A054214, A054215, A054216, A030465, A030466, A030467.

Sequence in context: A393287 A227168 A100252 * A255868 A385714 A289138

Adjacent sequences: A020337 A020338 A020339 * A020341 A020342 A020343

KEYWORD

base,nonn

AUTHOR

David W. Wilson

STATUS

approved

URL: https://oeis.org/A020340

⇱ A020340 - OEIS