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A121359 Greatest prime factor of pyramidal number A000292(n). 0
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

Cf. A000292 Tetrahedral (or pyramidal) numbers: C(n+2,3) = n(n+1)(n+2)/6.

LINKS

Table of n, a(n) for n=3..75.

FORMULA

a(n)=gpf(n(n+1)(n+2)/6), n=3,4,...

MATHEMATICA

FactorInteger[#][[-1, 1]]&/@Binomial[Range[2, 80]+2, 3] (* Harvey P. Dale, Jan 31 2013 *)

CROSSREFS

Cf. A000292.

Sequence in context: A197695 A245083 A233565 * A082087 A263317 A256300

Adjacent sequences:  A121356 A121357 A121358 * A121360 A121361 A121362

KEYWORD

nonn

AUTHOR

Zak Seidov, Sep 06 2006

STATUS

approved

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Last modified December 10 04:15 EST 2019. Contains 329885 sequences. (Running on oeis4.)