A374489 a(n) = floor(Sum_{k=n^4..(n+1)^4} k^(1/4)).
1, 26, 171, 628, 1685, 3726, 7231, 12776, 21033, 32770, 48851, 70236, 97981, 133238, 177255, 231376, 297041, 375786, 469243, 579140, 707301, 855646, 1026191, 1221048, 1442425, 1692626, 1974051, 2289196, 2640653, 3031110, 3463351, 3940256, 4464801, 5040058, 5669195
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
Programs
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Mathematica
LinearRecurrence[{5,-10,10,-5,1},{1,26,171,628,1685},40] (* Harvey P. Dale, Nov 07 2024 *)
Formula
a(n) = 4*n^4+8*n^3+8*n^2+5*n+1.
From Stefano Spezia, Jul 09 2024: (Start)
G.f.: (1 + 21*x + 51*x^2 + 23*x^3)/(1 - x)^5.
E.g.f.: exp(x)*(1 + 25*x + 60*x^2 + 32*x^3 + 4*x^4). (End)