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A093712
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Repeatedly subtract largest prime from n until either a prime or 1 remains.
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0
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1, 2, 3, 31, 5, 51, 7, 71, 72, 73, 11, 111, 13, 131, 132, 133, 17, 171, 19, 191, 192, 193, 23, 231, 232, 233, 2331, 235, 29, 291, 31, 311, 312, 313, 3131, 315, 37, 371, 372, 373, 41, 411, 43, 431, 432, 433, 47, 471, 472, 473, 4731, 475, 53, 531, 532, 533, 5331, 535
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OFFSET
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1,2
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COMMENTS
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The representation as strings of primes is similar to the Zeckendorf expansion, A035514's strings of Fibonacci numbers.
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LINKS
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EXAMPLE
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a(8) = 71 because 8 = 7 + 1.
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PROG
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(PARI) a(n) = {lp = List(); while(n!= 1 && ! isprime(n), p = precprime(n-1); listput(lp, p); n -= p; ); listput(lp, n); return (sum(i=1, #lp, 10^(#lp - i)*lp[i])); } \\ Michel Marcus, Jun 10 2013
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CROSSREFS
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KEYWORD
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easy,nonn,base
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AUTHOR
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STATUS
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approved
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