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 A330681 a(n) = A283980(A025487(n)). 3
 1, 6, 36, 30, 216, 180, 1296, 1080, 210, 7776, 900, 6480, 1260, 46656, 5400, 38880, 7560, 279936, 32400, 6300, 233280, 2310, 27000, 45360, 1679616, 194400, 37800, 1399680, 13860, 162000, 272160, 10077696, 1166400, 226800, 8398080, 83160, 972000, 44100, 1632960, 60466176, 189000, 6998400, 69300, 810000, 1360800 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS After 1, contains only the least representatives of such prime signatures where the maximal exponent occurs more than once. However, here the terms are not in ascending order. LINKS Antti Karttunen, Table of n, a(n) for n = 1..15703 FORMULA a(n) = A283980(A025487(n)). A046523(a(n)) = a(n). A085089(a(n)) = A101296(a(n)) = A330683(n). EXAMPLE For example, 180 = 2^2 * 3^2 * 5^1 is present, because the maximal exponent in its prime factorization is 2, which occurs as an exponent of both 2 and 3, and because 180 is the minimal representative of the prime signature (2,2,1), as A046523(180) = 180. PROG (PARI) A283980(n) = {my(f=factor(n)); prod(i=1, #f~, my(p=f[i, 1], e=f[i, 2]); if(p==2, 6, nextprime(p+1))^e)}; \\ From A283980 A025487list(e) = { my(lista = List([1, 2]), i=2, u = 2^e, t); while(lista[i] != u, if(2*lista[i] <= u, listput(lista, 2*lista[i]); t = A283980(lista[i]); if(t <= u, listput(lista, t))); i++); vecsort(Vec(lista)); }; \\ Returns a list of terms up to the term 2^e. v025487 = A025487list(64); A025487(n) = v025487[n]; A330681(n) = A283980(A025487(n)); CROSSREFS Cf. A025487, A046523, A283980, A329899, A330683. Sequence in context: A001311 A137868 A070401 * A070400 A222929 A222784 Adjacent sequences:  A330678 A330679 A330680 * A330682 A330683 A330684 KEYWORD nonn AUTHOR Antti Karttunen, Dec 26 2019 STATUS approved

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Last modified May 11 13:41 EDT 2021. Contains 343791 sequences. (Running on oeis4.)