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A171080 a(n) = Product_{3 <= q <= 2n+1, q prime} q^floor((2n/(q-1)). 5
1, 3, 45, 945, 14175, 467775, 638512875, 1915538625, 488462349375, 194896477400625, 32157918771103125, 2218896395206115625, 3028793579456347828125, 9086380738369043484375, 3952575621190533915703125, 28304394023345413370350078125, 7217620475953080409439269921875 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

F. Hirzebruch, Topological Methods in Algebraic Geometry, Springer, 3rd. ed., 1966; Lemma 1.5.2, p. 13.

LINKS

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

MAPLE

f:=proc(n) local q, t1; t1:=1; for q from 3 to 2*n+1 do if isprime(q) then t1:=t1*q^floor(2*n/(q-1)); fi; od; t1; end;

MATHEMATICA

a[n_] := Product[If[PrimeQ[q], q^Floor[2 n/(q - 1)], 1], {q, 3, 2 n + 1}]

Table[a[n], {n, 0, 20}] (* Wolfgang Hintze, Oct 03 2014 *)

CROSSREFS

Cf. A091137

Sequence in context: A036278 A225149 A154289 * A188681 A012827 A012769

Adjacent sequences:  A171077 A171078 A171079 * A171081 A171082 A171083

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Sep 06 2010

STATUS

approved

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Last modified October 23 22:26 EDT 2017. Contains 293833 sequences.