A248027 Sum over each antidiagonal of A248017.
0, 0, 0, 4, 69, 554, 3100, 13288, 47492, 147050, 407568, 1030912, 2419025, 5324684, 11099416, 22065120, 42085344, 77378556, 137705904, 237996060, 400624581, 658434694, 1058839380, 1669118984, 2583424948, 3931632406, 5890783808, 8699293304, 12674960961
Offset: 1
Keywords
Examples
a(1)..a(9) are formed as follows: . Antidiagonals of A248017 n a(n) . 0 1 0 . 0 0 2 0 . 0 0 0 3 0 . 0 2 2 0 4 4 . 1 14 39 14 1 5 69 . 3 66 208 208 66 3 6 554 . 12 198 794 1092 794 198 12 7 3100 . 28 508 2196 3912 3912 2196 508 28 8 13288 .66 1092 5231 10626 13462 10626 5231 1092 66 9 47492
Links
- Christopher Hunt Gribble, Table of n, a(n) for n = 1..10000
Crossrefs
Cf. A248017.
Programs
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Maple
b := proc (n::integer, k::integer)::integer; (4*k^5*n^5 - 40*k^4*n^4 + 140*k^3*n^3 + 2*k^5 + 20*k^4*n + 30*k^3*n^2 + 30*k^2*n^3 + 20*k*n^4 + 2*n^5 - 40*k^4 - 120*k^3*n - 185*k^2*n^2 - 120*k*n^3 - 40*n^4 + 160*k^3 - 20*k^2*n - 20*k*n^2 + 160*n^3 - 80*k^2 + 36*k*n - 80*n^2 + 48*k + 48*n + 45 + (- 30*k^2*n^3 - 20*k*n^4 - 2*n^5 - 15*k^2*n^2 + 120*k*n^3 + 40*n^4 + 20*k*n^2 - 160*n^3 + 60*k*n + 80*n^2 - 48*n - 45)*(-1)^k + (- 2*k^5 - 20*k^4*n - 30*k^3*n^2 + 40*k^4 + 120*k^3*n - 15*k^2*n^2 - 160*k^3 + 20*k^2*n + 80*k^2 + 60*k*n - 48*k - 45)*(-1)^n + (15*k^2*n^2 - 60*k*n + 45)*(-1)^k*(-1)^n)/1920; end proc; for j to 10000 do a := 0; for k from j by -1 to 1 do n := j-k+1; a := a+b(n, k); end do; printf("%d, ", a); end do;
Formula
Empirically, a(n) = (2*n^11 + 22*n^10 + 22*n^9 - 462*n^8 - 1122*n^7 + 7392*n^6 - 3509*n^5 - 25663*n^4 + 48950*n^3 - 22869*n^2 - 65133*n + 41580 - (693*n^5 + 3465*n^4 - 6930*n^3 - 45045*n^2 + 27027*n + 41580)*(-1)^n)/2661120.
Empirical g.f.: -x^4*(x^11 + 2*x^10 - 7*x^9 - 10*x^8 - 28*x^7 - 170*x^6 - 484*x^5 - 538*x^4 - 461*x^3 - 176*x^2 - 45*x - 4) / ((x - 1)^12*(x + 1)^6). - Colin Barker, Apr 21 2015
Extensions
Terms corrected and extended by Christopher Hunt Gribble, Apr 17 2015
Comments