A252464 a(1) = 0, a(2n) = 1 + a(n), a(2n+1) = 1 + a(A064989(2n+1)); also binary width of terms of A156552 and A243071.

0, 1, 2, 2, 3, 3, 4, 3, 3, 4, 5, 4, 6, 5, 4, 4, 7, 4, 8, 5, 5, 6, 9, 5, 4, 7, 4, 6, 10, 5, 11, 5, 6, 8, 5, 5, 12, 9, 7, 6, 13, 6, 14, 7, 5, 10, 15, 6, 5, 5, 8, 8, 16, 5, 6, 7, 9, 11, 17, 6, 18, 12, 6, 6, 7, 7, 19, 9, 10, 6, 20, 6, 21, 13, 5, 10, 6, 8, 22, 7, 5, 14, 23, 7, 8, 15, 11, 8, 24, 6, 7, 11, 12, 16, 9, 7, 25, 6, 7, 6, 26, 9, 27

Offset

1,3

Comments

a(n) tells how many iterations of A252463 are needed before 1 is reached, i.e., the distance of n from 1 in binary trees like A005940 and A163511.

Similarly for A253553 in trees A253563 and A253565. - Antti Karttunen, Apr 14 2019

Links

Antti Karttunen, Table of n, a(n) for n = 1..8192

Formula

a(1) = 0; for n > 1: a(n) = 1 + a(A252463(n)).

a(n) = A029837(1+A243071(n)). [a(n) = binary width of terms of A243071.]

a(n) = A029837(A005941(n)) = A029837(1+A156552(n)). [Also binary width of terms of A156552.]

Other identities. For all n >= 1:

a(A000040(n)) = n.

a(A001248(n)) = n+1.

a(A030078(n)) = n+2.

And in general, a(prime(n)^k) = n+k-1.

a(A000079(n)) = n. [I.e., a(2^n) = n.]

For all n >= 2:

a(n) = A001222(n) + A061395(n) - 1 = A001222(n) + A252735(n) = A061395(n) + A252736(n) = 1 + A252735(n) + A252736(n).

a(n) = A325134(n) - 1. - Gus Wiseman, Apr 02 2019

From Antti Karttunen, Apr 14 2019: (Start)

a(1) = 0; for n > 1: a(n) = 1 + a(A253553(n)).

a(n) = A001221(n) + A297167(n) = A297113(n) + A297155(n).

(End).

Example

From Gus Wiseman, Apr 02 2019: (Start)
The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k), so a(n) is the size of the inner lining of the integer partition with Heinz number n, which is also the size of the largest hook of the same partition. For example, the partition with Heinz number 715 is (6,5,3), with diagram
  o o o o o o
  o o o o o
  o o o
which has inner lining
          o o
      o o o
  o o o
and largest hook
  o o o o o o
  o
  o
both of which have size 8, so a(715) = 8.
(End)

Mathematica

Table[If[n==1, 1, PrimeOmega[n]+PrimePi[FactorInteger[n][[-1, 1]]]]-1, {n, 100}] (* Gus Wiseman, Apr 02 2019 *)

Prog

(Scheme, two different versions)
;; Memoization-macro definec can be found from Antti Karttunen's IntSeq-library
(definec (A252464 n) (if (<= n 1) 0 (+ 1 (A252464 (A252463 n)))))
(define (A252464 n) (A029837 (+ 1 (A243071 n))))
(define (A252464 n) (A029837 (A005941 n)))
(PARI)
A061395(n) = if(n>1, primepi(vecmax(factor(n)[, 1])), 0);
A252464(n) = (bigomega(n) + A061395(n) - 1); \\ Antti Karttunen, Apr 14 2019
(Python)
from sympy import primepi, primeomega, primefactors
def A252464(n): return primeomega(n)+primepi(max(primefactors(n)))-1 if n>1 else 0 # Chai Wah Wu, Jul 17 2023

Crossrefs

Cf. A000040, A000079, A001221, A001222, A005940, A029837, A061395, A156552 (A005941), A163511, A243071, A252461, A252463, A252735, A252736, A252759, A253553, A253563, A253565, A297113, A297155, A297167, A324870, A324872.

Right edge of irregular triangle A265146.

Cf. also A246348.

Cf. A052126, A056239, A093641, A112798, A257990, A325133, A325134, A325135.

Sequence in context: A322163 A075167 A253555 * A324861 A324863 A332894

Adjacent sequences: A252461 A252462 A252463 * A252465 A252466 A252467

Keyword

nonn

Author

Antti Karttunen, Dec 20 2014

Status

approved