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Search: id:A109020
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A109020 (2*7^n - 3*3^n + 1)/6. +0
2
0, 1, 12, 101, 760, 5481, 38852, 273421, 1918320, 13441361, 94128892, 659020341, 4613496680, 32295539641, 226071966132, 1582513328861, 11077621999840, 77543440092321, 542804338926572, 3799631147326981, 26597420355811800, 186181949464251401, 1303273667170466212 (list; graph; listen)
OFFSET

0,3

COMMENT

Number of incongruent integer-edged Heron triangles whose circumdiameter is the product of n distinct primes of shape 4k + 1.

CROSSREFS

Sequence in context: A085374 A016283 A008547 this_sequence A099299 A022736 A082151

Adjacent sequences: A109017 A109018 A109019 this_sequence A109021 A109022 A109023

KEYWORD

nonn

AUTHOR

Alex Fink and R. K. Guy, Aug 18 2005

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Last modified September 6 09:40 EDT 2008. Contains 143480 sequences.


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