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A280302 Smallest k such that (n+1)^k - n^k is divisible by a square > 1. 10
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.
a(n) <= p^2 - p, where p = A053670(n). - Jinyuan Wang, May 15 2020
LINKS
EXAMPLE
a(1) = 6 is because (1+1)^6 - 1^6 = 63 is divisible by 9 = 3^2.
PROG
(PARI) a(n) = {my(k = 1); while (issquarefree((n+1)^k - n^k), k++); k; } \\ Michel Marcus, Jan 14 2017
CROSSREFS
Sequence in context: A052193 A347632 A144763 * A083478 A328202 A306368
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Lars Blomberg, Jan 10 2017
STATUS
approved

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Last modified June 22 02:28 EDT 2024. Contains 373561 sequences. (Running on oeis4.)