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A284812
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Numbers n such that n' = d_1^1 + d_2^2 + ... + d_k^k where d_1, d_2, ..., d_k are the digits of n, with MSD(n) = d_1 and LSD(n) = d_k, and n' is the arithmetic derivative of n.
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1
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4, 34, 78, 47863, 67277, 472621, 525038, 5576423, 7541551, 12485411, 13600033, 41777431, 48288701, 64979641, 97807441, 136272511, 153060223, 201916441, 214821521, 225015223
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OFFSET
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1,1
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LINKS
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EXAMPLE
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47863' = 2104 = 4^1 + 7^2 + 8^3 + 6^4 + 3^5.
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MAPLE
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with(numtheory): P:=proc(q) local a, k, n, p; for n from 1 to q do a:=convert(n, base, 10);
if add(a[k]^(nops(a)-k+1), k=1..nops(a))=n*add(op(2, p)/op(1, p), p=ifactors(n)[2])
then print(n); fi; od; end: P(10^9);
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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STATUS
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approved
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