A127963 Number of 1's in A127962(n).

2, 3, 4, 6, 7, 9, 10, 12, 16, 22, 31, 40, 51, 64, 84, 96, 100, 157, 174, 351, 855, 1309, 1770, 2904, 5251, 5346, 5640, 6196, 7240, 21369, 41670, 47685, 58620, 63516, 69469, 70540, 133509, 134994, 187161, 493096, 2015700

Offset

1,1

Links

Table of n, a(n) for n=1..41.

Formula

a(n) = A000120(A000979(n)). - Michel Marcus, Nov 07 2013

a(n) = A007953(A127962(n)). - Amiram Eldar, Jul 23 2023

Mathematica

b = {}; Do[c = 1 + Sum[2^(2n - 1), {n, 1, x}]; If[PrimeQ[c], AppendTo[b, c]], {x, 0, 1000}]; a = {}; Do[AppendTo[a, FromDigits[IntegerDigits[b[[x]], 2]]], {x, 1, Length[b]}]; d = {}; Do[AppendTo[d, DigitCount[a[[x]], 10, 1]], {x, 1, Length[a]}]; d (* Artur Jasinski, Feb 09 2007 *)
DigitCount[#, 2, 1]& /@ Select[Table[(2^p + 1)/3, {p, Prime[Range[300]]}], PrimeQ] (* Amiram Eldar, Jul 23 2023 *)

Crossrefs

Cf. A000120, A000978, A000979, A007953, A124400, A126614, A127936, A127955, A127956, A127957, A127958, A127961, A127962.

Sequence in context: A111333 A047701 A164528 * A031403 A189578 A190859

Adjacent sequences: A127960 A127961 A127962 * A127964 A127965 A127966

Keyword

nonn,base,more

Author

Artur Jasinski, Feb 09 2007

Extensions

a(22)-a(29) from Vincenzo Librandi, Mar 31 2012

a(30)-a(41) from Amiram Eldar, Jul 23 2023

Status

approved