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A271266 a(n) = Product_{k=1..n} (k^2 + 21). 0
1, 22, 550, 16500, 610500, 28083000, 1600731000, 112051170000, 9524349450000, 971483643900000, 117549520911900000, 16692031969489800000, 2754185274965817000000, 523295202243505230000000, 113555058886840634910000000, 27934544486162796187860000000, 7737868822667094544037220000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Yin et al. prove that a(n) is never a square for n > 0.

LINKS

Table of n, a(n) for n=0..16.

Q. Yin, Q. Tan and Y. Luo, p-Adic Valuation of (12+21)...(n2+21) and Applications, Southeast Asian Bulletin of Mathematics, Vol. 39(5) (2015) page: 747-754.

MATHEMATICA

Table[Product[k^2 + 21, {k, n}], {n, 0, 16}] (* Michael De Vlieger, Apr 03 2016 *)

PROG

(PARI) a(n) = prod(k=1, n, (k^2+21));

CROSSREFS

Cf. A101686, A241851.

Sequence in context: A182610 A320766 A203456 * A333899 A239652 A223883

Adjacent sequences:  A271263 A271264 A271265 * A271267 A271268 A271269

KEYWORD

nonn

AUTHOR

Michel Marcus, Apr 03 2016

STATUS

approved

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Last modified July 30 11:46 EDT 2021. Contains 346359 sequences. (Running on oeis4.)