A328834 Square root of the prime factor form (A276086) of the primorial base expansion, computed for such numbers for which it is a square.

1, 3, 5, 15, 25, 75, 7, 21, 35, 105, 175, 525, 49, 147, 245, 735, 1225, 3675, 343, 1029, 1715, 5145, 8575, 25725, 11, 33, 55, 165, 275, 825, 77, 231, 385, 1155, 1925, 5775, 539, 1617, 2695, 8085, 13475, 40425, 3773, 11319, 18865, 56595, 94325, 282975, 121, 363, 605, 1815, 3025, 9075, 847, 2541, 4235, 12705, 21175, 63525, 5929, 17787

Offset: 1

Author

Antti Karttunen, Oct 30 2019

Keywords

• nonn

Comments

All terms are odd.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..9072
• Index entries for sequences related to primorial base

Crossrefs

Cf. A000196, A276086, A328849, A328770.

Programs

Mathematica

With[{b = MixedRadix[Reverse@ Prime@ Range@ 20]}, Select[Array[Sqrt@ Function[k, Times @@ Power @@@ # &@ Transpose@ {Prime@ Range@ Length@ k, Reverse@ k}]@ IntegerDigits[#, b] &, 10^3, 0], IntegerQ]] (* Michael De Vlieger, Oct 30 2019 *)

Formula

a(n) = A276086(A328770(n)) = A000196(A276086(A328849(n))).