A329132 Numbers whose augmented differences of prime indices are a periodic sequence.

4, 8, 15, 16, 32, 55, 64, 90, 105, 119, 128, 225, 253, 256, 403, 512, 540, 550, 697, 893, 935, 1024, 1155, 1350, 1357, 1666, 1943, 2048, 2263, 3025, 3071, 3150, 3240, 3375, 3451, 3927, 3977, 4096, 4429, 5123, 5500, 5566, 6731, 7735, 8083, 8100, 8192, 9089

Offset

1,1

Comments

The augmented differences aug(y) of an integer partition y of length k are given by aug(y)_i = y_i - y_{i + 1} + 1 if i < k and aug(y)_k = y_k. For example, aug(6,5,5,3,3,3) = (2,1,3,1,1,3).

A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.

A sequence is periodic if its cyclic rotations are not all different.

Links

Table of n, a(n) for n=1..48.

Example

The sequence of terms together with their augmented differences of prime indices begins:
     4: (1,1)
     8: (1,1,1)
    15: (2,2)
    16: (1,1,1,1)
    32: (1,1,1,1,1)
    55: (3,3)
    64: (1,1,1,1,1,1)
    90: (2,1,2,1)
   105: (2,2,2)
   119: (4,4)
   128: (1,1,1,1,1,1,1)
   225: (1,2,1,2)
   253: (5,5)
   256: (1,1,1,1,1,1,1,1)
   403: (6,6)
   512: (1,1,1,1,1,1,1,1,1)
   540: (2,1,1,2,1,1)
   550: (3,1,3,1)
   697: (7,7)
   893: (8,8)

Mathematica

primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
aperQ[q_]:=Array[RotateRight[q, #1]&, Length[q], 1, UnsameQ];
aug[y_]:=Table[If[i<Length[y], y[[i]]-y[[i+1]]+1, y[[i]]], {i, Length[y]}];
Select[Range[100], !aperQ[aug[primeMS[#]//Reverse]]&]

Crossrefs

Complement of A329133.

These are the Heinz numbers of the partitions counted by A329143.

Periodic binary words are A152061.

Periodic compositions are A178472.

Numbers whose binary expansion is periodic are A121016.

Numbers whose prime signature is periodic are A329140.

Numbers whose differences of prime indices are periodic are A329134.

Cf. A000961, A027375, A056239, A112798, A325356, A325389, A325394, A328594, A329135, A329136, A329139.

Sequence in context: A104101 A130826 A312708 * A312709 A312710 A312711

Adjacent sequences: A329129 A329130 A329131 * A329133 A329134 A329135

Keyword

nonn

Author

Gus Wiseman, Nov 06 2019

Status

approved