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A229063
Volume of the Johnson square pyramid (rounded down) with all the edge lengths equal to n.
2
0, 1, 6, 15, 29, 50, 80, 120, 171, 235, 313, 407, 517, 646, 795, 965, 1158, 1374, 1616, 1885, 2182, 2509, 2867, 3258, 3682, 4142, 4639, 5174, 5748, 6363, 7021, 7723, 8470, 9264, 10105, 10996, 11939, 12933, 13981, 15084, 16244, 17462, 18739, 20078, 21478, 22942
OFFSET
1,3
COMMENTS
Johnson square pyramid: Square base with four equilateral triangular-faces. All the edge lengths are equal to n.
LINKS
FORMULA
a(n) = floor(n^3*sqrt(2)/6)
EXAMPLE
a(9)=171: Volume= sqrt(2)/6*n^3= sqrt(2)/6*9^3= 171.8269478 and floor(171.8269478)= 171.
MAPLE
A229063 := proc(n)
floor(n^3*sqrt(2)/6) ;
end proc:
MATHEMATICA
Table[Floor[k^3*Sqrt[2]/6], {k, 1, 100}]
CROSSREFS
Cf. A228189.
Sequence in context: A200184 A005286 A298877 * A025212 A024972 A048749
KEYWORD
nonn
AUTHOR
K. D. Bajpai, Sep 17 2013
STATUS
approved