A122205 Number of finite sequences b with b(0) = 1, b(i+1) = b(i)+d where d|b(i), ending with n.

1, 1, 1, 2, 2, 5, 5, 12, 17, 31, 31, 96, 96, 197, 324, 629, 629, 1695, 1695, 4374, 6266, 10671, 10671, 34402, 38776, 73274, 109371, 223510, 223510, 634267, 634267, 1527075, 2172013, 3699717, 4557494, 12736034, 12736034, 25473763, 38283071

Offset: 1

Author

Franklin T. Adams-Watters, Aug 25 2006

Keywords

• nonn

Crossrefs

Cf. A117497, A122206, A067951.

Formula

a(1) = 1, for n>1, a(n) = sum_{d|n, d

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