A187064 Coefficients in numerator polynomial of: Sum (k=1 to n) of x^k/(1-x^k).

1, 2, 1, 3, 4, 3, 1, 4, 5, 7, 5, 3, 1, 5, 11, 19, 24, 26, 22, 16, 9, 4, 1, 6, 7, 15, 18, 23, 21, 21, 15, 11, 6, 3, 1, 7, 15, 32, 52, 77, 99, 120, 128, 130, 119, 102, 79, 57, 36, 21, 10, 4, 1, 8, 17, 36, 58, 93, 125, 165, 193, 220, 229, 231, 213, 191, 157, 124

Offset: 1

Author

Mats Granvik, Mar 07 2011

Keywords

• nonn
• tabf

Comments

The number of elements per row begins: 1,2,4,6,10,12,18,... which appears to be A002088.

Row sums begin: 1,3,11,25,137,147,1089,... which appears to be A025529.

Examples

			Table begins:
1,
2,1,
3,4,3,1,
4,5,7,5,3,1,
5,11,19,24,26,22,16,9,4,1,
6,7,15,18,23,21,21,15,11,6,3,1,
7,15,32,52,77,99,120,128,130,119,102,79,57,36,21,10,4,1,
Polynomials begin:
-(1*x^1)/(x^1-1)
-(2*x^2+1*x)/(x^2-1)
-(3*x^4+4*x^3+3*x^2+1*x^1)/(x^4+x^3-x^1-1)
-(4*x^6+5*x^5+7*x^4+5*x^3+3*x^2+1*x^1)/(x^6+x^5+x^4-x^2-x^1-1)
		

Programs

PARI

row(n) = v = Vec(numerator(sum(k=1, n, x^k/(1-x^k)))); for (k=1, #v-1, print1(abs(v[k]), ", ")); /*print*/; \\ Michel Marcus, Jun 11 2014

Extensions

More terms from Michel Marcus, Jun 11 2014