login
A338514
Numbers k such that k and k+1 are both divisible by the total binary weight of their divisors (A093653).
3
1, 2, 54, 2119, 11100, 13727, 14382, 15799, 16399, 20159, 20950, 33421, 34617, 36328, 36396, 39400, 42198, 42438, 42650, 46253, 46873, 50370, 55368, 56600, 58793, 67013, 67320, 69023, 72325, 76057, 86393, 90781, 92906, 93216, 105909, 132088, 134028, 134823, 140466
OFFSET
1,2
COMMENTS
Numbers k such that k and k+1 are both in A093705, or, equivalently, k is divisible by A093653(k) and k+1 is divisible by A093653(k+1).
LINKS
EXAMPLE
1 is a term since 1 and 2 are both terms of A093705.
MATHEMATICA
divQ[n_] := Divisible[n, DivisorSum[n, DigitCount[#, 2, 1] &]]; q1 = divQ[1]; Reap[Do[q2 = divQ[n]; If[q1 && q2, Sow[n - 1]]; q1 = q2, {n, 2, 10^5}]][[2, 1]]
SequencePosition[Table[If[Divisible[n, Total[DigitCount[Divisors[n], 2, 1]]], 1, 0], {n, 150000}], {1, 1}][[All, 1]] (* Harvey P. Dale, Jun 14 2022 *)
CROSSREFS
Similar sequences: A330927, A330931, A334345, A338452.
Sequence in context: A305693 A357421 A071798 * A123686 A122418 A069788
KEYWORD
nonn,base
AUTHOR
Amiram Eldar, Oct 31 2020
STATUS
approved