cp's OEIS Frontend

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.

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A334346 Starts of runs of 3 consecutive binary Moran numbers (A334344).

Original entry on oeis.org

126866286, 133542126, 148891086, 150959502, 173668302, 207567342, 227950542, 257154606, 263874222, 284421582, 295075566, 331190766, 373024206, 390589326, 392805486, 393817806, 395760366, 397921806, 441314766, 459700686, 459990702, 516188142, 527006286, 586869966
Offset: 1

Views

Author

Amiram Eldar, Apr 23 2020

Keywords

Examples

			126866286 is a term since 126866286/A000120(126866286) = 7048127, 126866287/A000120(126866287) = 6677173 and 126866288/A000120(126866288) = 7929143 are all prime numbers.
		

Crossrefs

Subsequence of A330932, A334344 and A334345.

Programs

  • Mathematica
    binMoranQ[n_] := PrimeQ[n / DigitCount[n, 2, 1]]; bin = binMoranQ /@ Range[3]; seq = {}; Do[If[And @@ bin, AppendTo[seq, k - 3]]; bin = Join[Rest[bin], {binMoranQ[k]}], {k, 4, 2 * 10^8}]; seq

A338514 Numbers k such that k and k+1 are both divisible by the total binary weight of their divisors (A093653).

Original entry on oeis.org

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

Views

Author

Amiram Eldar, Oct 31 2020

Keywords

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).

Examples

			1 is a term since 1 and 2 are both terms of A093705.
		

Crossrefs

Similar sequences: A330927, A330931, A334345, A338452.

Programs

  • 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 *)
Showing 1-2 of 2 results.