A343137 Positions of records in A188172.

1, 7, 63, 315, 945, 1575, 3465, 10395, 17325, 26775, 45045, 135135, 225225, 405405, 675675, 1576575, 2027025, 2297295, 3828825, 6891885, 11486475, 26801775, 34459425, 43648605, 72747675, 130945815, 218243025, 509233725, 654729075, 1003917915, 1527701175, 3011753745, 4583103525

Offset

1,2

Links

Table of n, a(n) for n=1..33.

Example

945 is in the sequence as A188172(945) = 4 via the divisors 7, 15, 63 and 135 and no positive integer < 945 has at least four such (7 (mod 8)) divisors.

Mathematica

Function[{s, r}, Map[FirstPosition[s, #][[1]] &, r]] @@ {#, Union@ FoldList[Max, #]} &@ Array[DivisorSum[#, 1 &, Mod[#, 8] == 7 &] &, 10^6] (* Michael De Vlieger, Apr 08 2021 *)

Crossrefs

Cf. A188172, A188226.

Sequence in context: A304895 A161201 A007291 * A188226 A055405 A100741

Adjacent sequences: A343134 A343135 A343136 * A343138 A343139 A343140

Keyword

nonn

Author

David A. Corneth, Apr 06 2021

Status

approved