A106227 Self-convolution 7th power equals A106226, which consists entirely of digits {0,1,2,3,4,5,6} after the initial terms {1,7}.

1, 1, -3, 13, -65, 351, -1989, 11650, -69900, 427167, -2648438, 16612947, -105215448, 671760933, -4318468133, 27926126547, -181520036139, 1185220461607, -7769787811032, 51117085986564, -337373170566291, 2233091754693676, -14819626688607761, 98582852441111688

Offset: 0

Author

Paul D. Hanna, May 01 2005

Keywords

• sign
• base

Examples

			A(x) = 1 + x - 3*x^2 + 13*x^3 - 65*x^4 + 351*x^5 - 1989*x^6 +-...
A(x)^7 = 1 + 7*x + x^7 + 4*x^14 + 6*x^21 + 5*x^28 + x^35 + 6*x^42 +...
A106226 = {1,7,0,0,0,0,0,1,0,0,0,0,0,0,4,0,0,0,0,0,0,6,...}.
		

Crossrefs

Cf. A106226, A106219, A106221, A106223, A106225.

Programs

PARI

{a(n)=local(A=1+7*x);if(n==0,1, for(j=1,n, for(k=0,6,t=polcoeff((A+k*x^j+x*O(x^j))^(1/7),j); if(denominator(t)==1,A=A+k*x^j;break))); return(polcoeff((A+x*O(x^n))^(1/7),n)))}