A227221 Volume of Johnson square pyramid placed upright on cube (rounded down) with edge lengths equal to n.
1, 9, 33, 79, 154, 266, 423, 632, 900, 1235, 1644, 2135, 2714, 3390, 4170, 5061, 6071, 7206, 8475, 9885, 11443, 13157, 15034, 17082, 19307, 21718, 24322, 27126, 30137, 33363, 36812, 40491, 44407, 48568, 52980, 57652, 62592, 67805, 73300, 79084, 85165, 91550, 98246
Offset: 1
Keywords
Examples
a(4) = 79: volume = sqrt(2)/6*k^3 + k^3 = sqrt(2)/6*4^3 + 4^3 = 79.0849... and floor(79.0849...) = 79.
Links
- Georg Fischer, Table of n, a(n) for n = 1..1000 [first 203 terms from _K. D. Bajpai_]
- Wikipedia, Square pyramid
Crossrefs
Cf. A224837.
Programs
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Maple
a:= n-> floor((sqrt(2)/6 + 1)*n^3): seq(a(n), n=1..43);
Comments