OFFSET
1,2
COMMENTS
19, the 3rd octahedral number, is the only prime platonic number. - Jean-François Alcover, Oct 11 2012
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
OEIS Wiki, Platonic numbers
MATHEMATICA
nn = 25; t1 = Table[n (n + 1) (n + 2)/6, {n, nn}]; t2 = Table[n^3, {n, nn}]; t3 = Table[(2*n^3 + n)/3, {n, nn}]; t4 = Table[n (3*n - 1) (3*n - 2)/2, {n, nn}]; t5 = Table[n (5*n^2 - 5*n + 2)/2, {n, nn}]; Select[Union[t1, t2, t3, t4, t5], # <= t1[[-1]] &] (* T. D. Noe, Oct 13 2012 *)
PROG
(Haskell)
a053012 n = a053012_list !! (n-1)
a053012_list = tail $ f
[a000292_list, a000578_list, a005900_list, a006566_list, a006564_list]
where f pss = m : f (map (dropWhile (<= m)) pss)
where m = minimum (map head pss)
-- Reinhard Zumkeller, Jun 17 2013
(PARI) listpoly(lim, poly[..])=my(v=List()); for(i=1, #poly, my(P=poly[i], x=variable(P), f=k->subst(P, x, k), n, t); while((t=f(n++))<=lim, listput(v, t))); Set(v)
list(lim)=my(n='n); listpoly(lim, n*(n+1)*(n+2)/6, n^3, (2*n^3+n)/3, n*(3*n-1)*(3*n-2)/2, n*(5*n^2-5*n+2)/2) \\ Charles R Greathouse IV, Oct 11 2016
CROSSREFS
KEYWORD
easy,nice,nonn
AUTHOR
Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Feb 22 2000
STATUS
approved