# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a348475 Showing 1-1 of 1 %I A348475 #9 Oct 22 2021 11:36:17 %S A348475 2,3,10,14,33,78,170,190,483,1218,2046,4070,5330,8385,33558,37842, %T A348475 47082,127490,169510,269445,825630,1250886,1404858,1969926,4270910, %U A348475 6988190,13239105,27506490,29387490,61019322,74958702,77319606,191617790,254235170,715103895,1549364190 %N A348475 a(n) = Product_{k=1..A003056(n)} prime(T(n,k)), where T(n,k) = k-th term in row n of A235791. %C A348475 Prime product compactification of A235791. %C A348475 All terms are squarefree. %H A348475 Michael De Vlieger, Table of n, a(n) for n = 1..10000 %e A348475 Row 3 of A235791 contains {3,1}, thus, a(3) = prime(3)*prime(1) = 5*2 = 10. %e A348475 Omar E. Pol's diagram of rows of A235791: %e A348475 . y row a(n) of A067255* a(n) %e A348475 Row _| -------------------------- %e A348475 1 _|1| -> 1 = 2 %e A348475 2 _|2 _| -> .1 = 3 %e A348475 3 _|3 |1| -> 1.1 = 10 %e A348475 4 _|4 _|1| -> 1..1 = 14 %e A348475 5 _|5 |2 _| -> .1..1 = 33 %e A348475 6 _|6 _|2|1| -> 11...1 = 78 %e A348475 7 _|7 |3 |1| -> 1.1...1 = 170 %e A348475 8 _|8 _|3 _|1| -> 1.1....1 = 190 %e A348475 9 _|9 |4 |2 _| -> .1.1....1 = 483 %e A348475 10 _|10 _|4 |2|1| -> 11.1.....1 = 1218 %e A348475 11 _|11 |5 _|2|1| -> 11..1.....1 = 2046 %e A348475 12 _|12 _|5 |3 |1| -> 1.1.1......1 = 4070 %e A348475 13 _|13 |6 |3 _|1| -> 1.1..1......1 = 5330 %e A348475 14 _|14 _|6 _|3|2 _| -> .11..1.......1 = 8385 %e A348475 15 _|15 |7 |4 |2|1| -> 11.1..1.......1 = 33558 %e A348475 16 _|16 _|7 |4 |2|1| -> 11.1..1........1 = 37842 %e A348475 ... %e A348475 * we replace 0 with "." for clarity. %t A348475 Table[Times @@ Array[Prime@ Ceiling[(n + 1)/# - (# + 1)/2] &, Floor[(Sqrt[8 n + 1] - 1)/2]], {n, 35}] %t A348475 (* Use the b-file to generate k rows of A235791 *) %t A348475 With[{k = 120}, MapIndexed[Reverse[PrimePi /@ FactorInteger[#][[All, 1]]] &, Import["https://oeis.org/A348475/b348475.txt", "Data"][[1 ;; k, -1]]]] (* _Michael De Vlieger_, Oct 21 2021 *) %Y A348475 Cf. A000040, A003056, A067255, A235791. %K A348475 nonn,easy %O A348475 1,1 %A A348475 _Michael De Vlieger_, Oct 19 2021 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE