This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
a(7) = 2^419 which has 127 decimal digits. a(35) = 2^15239 which has 4588 decimal digits.
a(5) = 30 because it is the first integer which has five nonprime divisors (1, 6, 10, 15 and 30; the divisors 2, 3 and 5 are prime). a(35) = 2^35 = 34359738368. a(71) = 2^71 = 2361183241434822606848. a(191) = 2^191 = 3138550867693340381917894711603833208051177722232017256448.
a055079 n = head [x | x <- [1..], a033273 x == n] -- Reinhard Zumkeller, Dec 16 2013
a = Table[0, {100} ]; Do[ c = Count[ PrimeQ[ Divisors[ n ] ], False]; If[ c < 101 && a[[ c ]] == 0, a[[ c ]] = n], {n, 2, 10077696} ];
Table[SelectFirst[Table[{n,Count[Divisors[n],?(!PrimeQ[#]&)]},{n,10000}],#[[2]]==k&],{k,34}][[;;,1]] (* The program generates the first 34 terms of the sequence. *) (* _Harvey P. Dale, Mar 04 2024 *)
sme(n) = {k = 1; while (sumdiv(k, d, ! isprime(d)) != n, k++); k;} \\ Michel Marcus, Dec 13 2013
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