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A121359
Greatest prime factor of pyramidal number A000292(n).
1
2, 5, 5, 7, 7, 7, 5, 11, 11, 13, 13, 13, 7, 17, 17, 19, 19, 19, 11, 23, 23, 23, 13, 13, 13, 29, 29, 31, 31, 31, 17, 17, 17, 37, 37, 37, 19, 41, 41, 43, 43, 43, 23, 47, 47, 47, 7, 17, 17, 53, 53, 53, 11, 19, 29, 59, 59, 61, 61, 61, 31, 13, 13, 67, 67, 67, 23, 71, 71, 73, 73, 73, 37
OFFSET
2,1
COMMENTS
a(n) <= n+2, with equality if n+2 is prime. - Robert Israel, Feb 16 2023
LINKS
FORMULA
a(n) = A006530(A000292(n)).
MAPLE
f:= n -> max(numtheory:-factorset(n*(n+1)*(n+2)/6)):
map(f, [$2..100]); # Robert Israel, Feb 16 2023
MATHEMATICA
FactorInteger[#][[-1, 1]]&/@Binomial[Range[2, 80]+2, 3] (* Harvey P. Dale, Jan 31 2013 *)
CROSSREFS
Sequence in context: A197695 A245083 A233565 * A082087 A263317 A256300
KEYWORD
nonn
AUTHOR
Zak Seidov, Sep 06 2006
EXTENSIONS
Offset corrected by Robert Israel, Feb 16 2023
STATUS
approved