OFFSET
1,2
COMMENTS
Shells (nexus numbers) of shells of the fifth powers (A000584).
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
O. Bagdasar, On some functions involving the lcm and gcd of integer tuples, Scientific Publications of the State University of Novi Pazar, Appl. Maths. Inform. and Mech., Vol. 6, 2 (2014), 91--100.
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
From R. J. Mathar, Sep 02 2008: (Start)
a(n) = A068236(n-2), n > 1.
G.f.: x + 30*x^2*(1+x)^2/(1-x)^4. (End)
E.g.f.: 30 + x + 10*exp(x)*(2*x^3 + 3*x - 3). - Stefano Spezia, Mar 20 2026
MAPLE
a:=`if`(n=1, 1, 20*n^3+10*n): 1, seq(a(n), n=1..35); # Muniru A Asiru, Dec 02 2018
MATHEMATICA
Table[If[n == 1, 1, 10*(n - 1)*(2*(n - 1)^2 + 1)], {n, 1, 50}] (* Vladimir Joseph Stephan Orlovsky, Jun 19 2011 *)(* modified by G. C. Greubel, Dec 01 2018 *)
PROG
(PARI) my(x='x+O('x^50)); Vec(x + 30*x^2*(1+x)^2/(1-x)^4) \\ G. C. Greubel, Dec 01 2018
(Magma) [n le 1 select 1 else 10*(n - 1)*(2*(n - 1)^2 + 1): n in [1..50]]; // G. C. Greubel, Dec 01 2018
(SageMath) s=(x + 30*x^2*(1+x)^2/(1-x)^4).series(x, 50); s.coefficients(x, sparse=False) # G. C. Greubel, Dec 01 2018
(GAP) Concatenation([1], List([1..35], n->20*n^3+10*n)); # Muniru A Asiru, Dec 02 2018
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Cecilia Rossiter (cecilia(AT)noticingnumbers.net), Dec 15 2004
EXTENSIONS
Edited by Ralf Stephan, Dec 16 2004
STATUS
approved