A232101 a(n) = A000217(A232097(n)) / n!.
1, 3, 1, 5, 1, 35, 5, 208, 8073, 36120, 1133197, 456667, 13535367, 2592766, 3409144, 24103053951, 1417826703, 486682892638
Offset: 1
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.
For n = 9, a(9)*(a(9) + 1) = 38570*38571 = (2*5*7*19*29)*(3*13*23*43) with 9 distinct prime factors.
With[{s = Map[PrimeNu[Times @@ #] &, Partition[Range[10^6], 2, 1]]}, Array[FirstPosition[s, n_/; n>=#][[1]] &, Max@ s]] (* Michael De Vlieger, Nov 02 2017 *)
a(n) = my(m=1); while(omega(m*(m+1)) < n, m++); m; \\ Michel Marcus, Jul 09 2018
n | a(n) | T(a(n)) = n^n * A342931(n). ----+----------+------------------------------------ 1 | 1 | 1 = 1^1 * 1. 2 | 7 | 28 = 2^2 * 7. 3 | 26 | 351 = 3^3 * 13. 4 | 511 | 130816 = 4^4 * 511. 5 | 3124 | 4881250 = 5^5 * 1562. 6 | 16767 | 140574528 = 6^6 * 3013. 7 | 823542 | 339111124653 = 7^7 * 411771. 8 | 33554431 | 562949936644096 = 8^8 * 33554431.
a(n) = my(k=1, m=n^n); while(k*(k+1)/2%m!=0, k++); k;
a(n) = { my(p = 2*n^n, f = factor(p), res = oo); for(i = 2^(#f~-1), 2^#f~-1, b = binary(i); pr = prod(j = 1, #f~, f[j,1]^(b[j]*f[j, 2])); ipr = p/pr; for(j = -1, 0, c = lift(chinese(Mod(-1-j, ipr), Mod(j, pr))); if(c > 0, res = min(res, c)))); res } \\ David A. Corneth, Mar 29 2021
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