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A156798
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n^4 + 5*n^2 + 4.
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4
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4, 10, 40, 130, 340, 754, 1480, 2650, 4420, 6970, 10504, 15250, 21460, 29410, 39400, 51754, 66820, 84970, 106600, 132130, 162004, 196690, 236680, 282490, 334660, 393754, 460360, 535090, 618580, 711490, 814504, 928330, 1053700, 1191370
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| a(n) = A002522(n)*A087475(n) = A000290(n)+A000290(A059100(n)) = A028552(A002522(n)).
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FORMULA
| (n^2 + 1)*(n^2 + 4) = n^2 + (n^2 + 2)^2.
G.f.: 2*(2-5*x+15*x^2-5*x^3+5*x^4)/(1-x)^5 [From Maksym Voznyy (voznyy(AT)mail.ru), Jul 26 2009]
a(0)=4, a(1)=10, a(2)=40, a(3)=130, a(4)=340, a(n)=5a(n-1)- 10a(n-2)+ 10a(n-3)-5a(n-4)+a(n-5) [From Harvey P. Dale, May 04 2011]
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MATHEMATICA
| Table[n^4+5n^2+4, {n, 0, 40}]
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PROG
| (MAGMA)[n^4+5*n^2+4: n in [0..50]]
(PARI) a(n)=n^4+5*n^2+4
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CROSSREFS
| Sequence in context: A149205 A149206 A149207 * A149208 A149209 A053792
Adjacent sequences: A156795 A156796 A156797 * A156799 A156800 A156801
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KEYWORD
| nonn,easy
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 16 2009
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EXTENSIONS
| G.f. proposed by Maksym Voznyy checked and corrected by R. J. Mathar, Sep 16 2009.
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