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Squareful


A squareful integer, also called nonsquarefree, is a positive integer divisible by the square of a prime. The first few are 4, 8, 9, 12, 16, 18, 20, 24, 25, ... (OEIS A013929). The greatest prime factors occurring with exponent at least two in the prime factorization of squareful integers are 2, 2, 3, 2, 2, 3, 2, 2, 5, 3, 2, 2, 3, ... (OEIS A046028). The least such prime factors are 2, 2, 3, 2, 2, 3, 2, 2, 5, 3, 2, 2, 2, ... (OEIS A046027).

No squareful Fibonacci numbers F_p are known with p prime.

The sequence of smallest terms in the first run of (at least) n consecutive squareful integers for n=1, 2, ... is 4, 8, 48, 242, 844, 22020, 217070, ... (OEIS A045882).


See also

Greatest Prime Factor, Least Prime Factor, Smarandache Near-to-Primorial Function, Squarefree

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References

Sloane, N. J. A. Sequences A013929, A045882, A046027, and A046028 in "The On-Line Encyclopedia of Integer Sequences."

Referenced on Wolfram|Alpha

Squareful

Cite this as:

Weisstein, Eric W. "Squareful." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Squareful.html

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