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Search: id:A124436
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| A124436 |
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a(1)=1, a(n)=p_i^d_i where p_i is i-th prime and d_i is i-th digit of a(n-1). |
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+0
1
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| 1, 2, 4, 16, 1458, 2918430506250, 7164640537512654203797788776525821310188011060
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Or a(n-1)= decimal encoding of the prime factorization of a(n). Cf. A068633 Let n = p^a*q^b... then a(n) = concatenation paqb..., A067599 Decimal encoding of the prime factorization of n.
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EXAMPLE
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a(4)=16, a(5)=2^1 * 3^6 = 1458;
a(6)= 2^1 * 3^4 * 5^5 * 7^8 = 2918430506250.
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MATHEMATICA
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a[1]=1; id[n_]:=id[n]=IntegerDigits[a[n-1]]; a[n_]:=a[n]= Times@@Table[Prime[i]^id[n][[i]], {i, 1, Length[id[n]]}]; {1, Table[a[n], {n, 2, 7}]}//Flatten
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CROSSREFS
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Cf. A067599, A068633.
Sequence in context: A001146 A114641 A001128 this_sequence A014221 A048872 A105510
Adjacent sequences: A124433 A124434 A124435 this_sequence A124437 A124438 A124439
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KEYWORD
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base,nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)gmail.com), Dec 16 2006
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