A087474 Triangle T(n,k), read by rows, in which the n-th row gives the n successive iterations of f(m) on A087473(n), where f(m) is product of the two numbers formed from the alternating digits of m.

1, 10, 0, 25, 10, 0, 39, 27, 14, 4, 77, 49, 36, 18, 8, 171, 77, 49, 36, 18, 8, 199, 171, 77, 49, 36, 18, 8, 577, 399, 351, 155, 75, 35, 15, 5, 887, 696, 594, 486, 368, 228, 56, 30, 0, 1592, 988, 784, 592, 468, 288, 224, 48, 32, 6, 2682, 1736, 988, 784, 592, 468, 288, 224

Offset: 0

Author

Amarnath Murthy and Paul D. Hanna, Sep 11 2003

Keywords

• nonn
• tabl
• base

Examples

			The 4th row is {77,49,36,18,8} since f(77)=49, f(49)=36, f(36)=18, f(18)=8.
{1},
{10,0},
{25,10,0},
{39,27,14,4},
{77,49,36,18,8},
{171,77,49,36,18,8},
{199,171,77,49,36,18,8},
{577,399,351,155,75,35,15,5},...
		

Crossrefs

Cf. A087471, A087472, A087473.

Formula

T(0, 0)=1, T(n, 0)=A087473(n), T(n, k+1) = f(T(n, k)), where f(m) is the product of the two numbers formed by the alternating digits of m.