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A280302 Smallest k such that (n+1)^k - n^k is divisible by a square > 1. 6
6, 10, 4, 2, 21, 20, 3, 20, 33, 6, 20, 2, 2, 5, 21, 6, 10, 6, 6, 4, 4, 2, 7, 2, 6, 3, 10, 4, 18, 6, 2, 10, 20, 6, 57, 17, 2, 14, 42, 2, 10, 10, 6, 39, 14, 4, 10, 20, 2, 21, 20, 6, 4, 21, 6, 20, 10, 2, 5, 2, 5, 2, 20, 6, 42, 14, 2, 6, 55, 6, 3, 7, 2, 42, 3, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(209) > 70.

LINKS

Lars Blomberg, Table of n, a(n) for n = 1..208

EXAMPLE

a(1) = 6 is because (1+1)^6 - 1^6 = 63 is divisible by a square 9.

PROG

(PARI) a(n) = {my(k = 1); while (issquarefree((n+1)^k - n^k), k++); k; } \\ Michel Marcus, Jan 14 2017

CROSSREFS

Cf. A049094, A237043, A280203, A280208, A280209, A280296, A282176, A282177.

Sequence in context: A295052 A052193 A144763 * A083478 A328202 A306368

Adjacent sequences:  A280299 A280300 A280301 * A280303 A280304 A280305

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Dec 31 2016

EXTENSIONS

More terms from Lars Blomberg, Jan 10 2017

STATUS

approved

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Last modified December 14 09:41 EST 2019. Contains 329979 sequences. (Running on oeis4.)