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A253638
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Number of zeros in the decimal expansion of 5^n.
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1
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0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 2, 1, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 0, 1, 2, 0, 3, 3, 2, 2, 3, 3, 4, 1, 1, 1, 4, 7, 4, 4, 5, 4, 3, 4, 6, 6, 3, 5, 2, 2, 0, 3, 4, 5, 6, 7, 8, 6, 6, 5, 7, 8, 8, 6, 8, 4, 3, 3, 6, 5, 4, 4, 8, 7, 4, 4, 3, 1, 4, 6, 4, 4, 6, 5, 6, 7, 6, 4, 4, 4, 6, 9, 12, 8, 5, 9, 7, 6, 4, 2, 9, 8, 5, 5, 3, 4, 6, 6, 9, 14, 12, 12, 12, 12, 13
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OFFSET
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0,14
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COMMENTS
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Probably a(58) is the last 0 term.
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LINKS
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FORMULA
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EXAMPLE
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5^57 = 6938893903907228377647697925567626953125, 2 zeros hence a(57) = 2,
5^58 = 34694469519536141888238489627838134765625, no zeros hence a(58) = 0,
5^59 = 173472347597680709441192448139190673828125, 3 zeros hence a(59) = 3.
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MATHEMATICA
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Table[Count[IntegerDigits[5^n], 0], {n, 0, 200}]
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PROG
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(PARI) a(n) = my(d = digits(5^n)); sum(i=1, #d, d[i] == 0); \\ Michel Marcus, Jan 15 2015
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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