A107731 Row 7 of the array in A107735.

1, 21, 141, 521, 1401, 3101, 6021, 10641, 17521, 27301, 40701, 58521, 81641, 111021, 147701, 192801, 247521, 313141, 391021, 482601, 589401, 713021, 855141, 1017521, 1202001, 1410501, 1645021, 1907641, 2200521, 2525901, 2886101, 3283521

Offset: 0

Author

N. J. A. Sloane, Jun 10 2005

Keywords

• nonn

References

• S. Mukai, An Introduction to Invariants and Moduli, Cambridge, 2003; see p. 483.

Programs

Mathematica

nn:=31; CoefficientList[Series[(1 + 16*x + 46*x^2 + 16*x^3 + x^4)/(1-x
)^5, {x,0,nn}], x] (* Georg Fischer, Apr 17 2020 *)

PARI

{a(n)= 1+ (n^2+n)* (n^2+n+1)* 10/3} /* Michael Somos, Mar 20 2007 */

Formula

a(n) = 1 + (n^2+n)*(n^2+n+1)*10/3. a(-1-n)= a(n). - Michael Somos, Mar 20 2007

G.f.: (1 + 16*x + 46*x^2 + 16*x^3 + x^4)/(1-x)^5. - Michael Somos, Mar 20 2007; corrected by Georg Fischer, Apr 17 2020

Extensions

More terms from Michael Somos, Mar 20 2007