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A372924
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a(n) = (sum_digits(n^3)-n)/3.
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1
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0, 0, 2, 2, 2, 1, 1, 1, 0, 3, -3, -1, 2, 2, 1, 1, 1, 0, 0, 3, -4, -1, -1, -2, -2, -2, 0, 0, -3, -1, -7, -1, -2, -2, -5, -3, -3, -6, -4, -4, -10, -5, -5, -5, -6, -9, -6, -10, -10, -7, -14, -11, -11, -6, -9, -9, -10, -10, -13, -11, -17, -11, -12, -15, -15, -13, -10
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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EXAMPLE
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For n=42, 42^3 = 74088 has sum of digits 27 so a(42) = (27 - 42)/3 = -5.
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MAPLE
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read("transforms"):
(digsum(n^3)-n)/3 ;
end proc:
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MATHEMATICA
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Table[(DigitSum[n^3] - n)/3, {n, 0, 100}] (* Paolo Xausa, Jul 03 2024 *)
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PROG
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(C)
#include <stdint.h>
#include <stdio.h>
int32_t sumDigits(int64_t num)
{
int32_t sum = 0;
while (num > 0)
{
sum += num % 10;
num /= 10;
}
return sum;
}
int main()
{
for (int64_t i=0; i<10000; ++i)
{
int64_t num = i * i * i;
int32_t sum = sumDigits(num);
printf("%ld, ", (sum - i)/3);
}
return 0;
}
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CROSSREFS
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KEYWORD
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sign,base,easy
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AUTHOR
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STATUS
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approved
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