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A101098 a(1)=1; thereafter, a(n+1) = 20*n^3 + 10*n. 6
1, 30, 180, 570, 1320, 2550, 4380, 6930, 10320, 14670, 20100, 26730, 34680, 44070, 55020, 67650, 82080, 98430, 116820, 137370, 160200, 185430, 213180, 243570, 276720, 312750, 351780, 393930, 439320, 488070, 540300, 596130, 655680, 719070, 786420, 857850 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Shells (nexus numbers) of shells of the fifth powers (A000584).
LINKS
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.
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)
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
(Sage) 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
Sequence in context: A100430 A159653 A369855 * A068236 A331434 A054559
KEYWORD
easy,nonn
AUTHOR
Cecilia Rossiter (cecilia(AT)noticingnumbers.net), Dec 15 2004
EXTENSIONS
Edited by Ralf Stephan, Dec 16 2004
STATUS
approved

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)