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A087474
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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.
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4
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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
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OFFSET
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0,2
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LINKS
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FORMULA
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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.
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EXAMPLE
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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},...
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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