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A122955
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Numbers k such that although the number of digits in 5^k is larger, the sum of the digits is less than that of the previous power of 5.
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0
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5, 11, 12, 13, 19, 25, 28, 29, 33, 35, 45, 46, 52, 53, 58, 59, 61, 62, 63, 65, 76, 78, 79, 81, 85, 88, 89, 91, 92, 95, 98, 101, 104, 108, 109, 114, 115, 116, 119, 125, 131, 136, 139, 144, 145, 158, 161, 162, 168, 169, 178, 179, 181, 184, 185, 189, 195, 197, 199, 207
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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11 is a term because 5^11 = 48828125 has 8 digits and digit sum 4+8+8+2+8+1+2+5 = 38 while 5^10 = 9765625 has 7 digits and digit sum 9+7+6+5+6+2+5 = 40.
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MATHEMATICA
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Select[ Range@ 208, Floor[Log[10, 5^# ]] > Floor[Log[10, 5^(# - 1)]] && Plus @@ IntegerDigits[5^# ] < Plus @@ IntegerDigits[5^(# - 1)] &]
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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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