13 lines
471 B
Text
13 lines
471 B
Text
chowla(n) := if(n=1) then 0 else divsum(n)-n-1$
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chowla_seq(n, start) := map(chowla, makelist(i,i,start,n))$
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chowla_seq(37, 1);
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chowla_numprimes(n) := length(sublist_indices(chowla_seq(n, 2), lambda([x], x=0)))$
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map(chowla_numprimes, makelist(10^i, i, 2, 7));
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chowla_perfects(n) := block(
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chowla_list: chowla_seq(n, 1),
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is_perfect(x) := if(x>n or x=0) then false else x=chowla_list[x+1],
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unique(sublist(chowla_list, is_perfect)+1))$
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chowla_perfects(10000);
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