A134631 a(n) = 5*n^5 - 3*n^3 + 2*n^2. Coefficients and exponents are the prime numbers in decreasing order.
0, 4, 144, 1152, 4960, 15300, 38304, 83104, 162432, 293220, 497200, 801504, 1239264, 1850212, 2681280, 3787200, 5231104, 7085124, 9430992, 12360640, 15976800, 20393604, 25737184, 32146272, 39772800, 48782500, 59355504, 71686944, 85987552, 102484260, 121420800, 143058304, 167675904, 195571332, 227061520
Offset: 0
Keywords
Examples
a(4)=4960 because 4^5=1024, 5*1024=5120, 4^3=64, 3*64=192, 4^2=16, 2*16=32 and we can write 5120 - 192 + 32 = 4960.
Links
- Harvey P. Dale, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (6, -15, 20, -15, 6, -1).
Programs
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Magma
[5*n^5-3*n^3+2*n^2: n in [0..50]]; // Vincenzo Librandi, Dec 14 2010
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Mathematica
Table[5n^5-3n^3+2n^2,{n,0,40}] (* or *) LinearRecurrence[{6,-15,20,-15,6,-1},{0,4,144,1152,4960,15300},40] (* Harvey P. Dale, Jan 20 2023 *)
Formula
a(n) = 5*n^5 - 3*n^3 + 2*n^2.
G.f.: 4x*(1+30x+87x^2+32x^3)/(1-x)^6. - R. J. Mathar, Nov 14 2007
Extensions
More terms from Vincenzo Librandi, Dec 14 2010