A111620 a(n) = 2*A111619/n.

1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1

Offset: 1

Author

Robert G. Wilson v, Aug 03 2005

Keywords

• nonn

Comments

A sequence of just 1's and 2's.

2n divided A111619 is: 2,2,2,2,1,2,1,2,2,2,2,2,1,2,1,2,2,2,1,2,1,2,1,1,1,1,2,1,2,2,2,2,1,2,1,1,1,1,1,2,1,1,1,1,1,1,1,2,2,1,2,1,1,1,1,1,1,2,1,1,1,1,1,2,2,2,1,2,2,2,1,2,..., Table[ n/g[n, n - 1], {n, 2, 144, 2}].

A111620(n) plus the n-th entry immediately above = 3.

Crossrefs

Cf. A111618.

Programs

Mathematica

f[n_] := f[n] = Block[{a}, a[0] = 1; a[l_] := a[l] = Block[{k = 1, s = Sum[ a[i]*x^i, {i, 0, l - 1}]}, While[ IntegerQ[ Last[ CoefficientList[ Series[(s + k*x^l)^(1/n), {x, 0, l}], x]]] != True, k++ ]; k]; Table[ a[j], {j, 0, 144}]]; g[n_, m_] := f[n][[m]]; Table[ 3 - n/g[n, n - 1], {n, 2, 144, 2}] (* or *) Table[ 2*g[n, n - 1]/n, {n, 2, 144, 2}]