OFFSET
1,1
COMMENTS
Johnson square pyramid: a square base with four equilateral triangular-faces. All the edge-lengths are equal.
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..1000 [a(613), a(864) corrected by Georg Fischer]
Wikipedia, Square pyramid
FORMULA
a(n) = floor((1+sqrt(3))*n^2).
EXAMPLE
a(3) = 24: Surface area = (1+sqrt(3))*3^2 = 24.588... and floor(24.588...) = 24.
MAPLE
a:= n-> floor((1+sqrt(3))*n^2):
seq(a(n), n=1..48);
MATHEMATICA
Table[Floor[(1+Sqrt[3])*k^2], {k, 500}]
PROG
(PARI) vector(500, k, floor((1+sqrt(3))*k^2))
(PARI) a(n)=n^2+sqrtint(3*n^4) \\ Charles R Greathouse IV, Sep 18 2013
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
K. D. Bajpai, Sep 18 2013
STATUS
approved