A087740 a(n) = 1 + abs(A004001(A005185(n)) - A005185(A004001(n))).

1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 1, 3, 3, 3, 2, 2, 2, 4, 1, 2, 2, 2, 2, 1, 2, 1, 2, 3, 3, 1, 1, 1, 3, 3, 1, 3, 2, 1, 1, 2, 1, 5, 5, 5, 5, 2, 2, 2, 2, 7, 1, 2, 2, 3, 3, 3, 2, 2, 1, 2, 2, 1, 2, 1, 2, 1, 2, 3, 2, 2, 6, 7, 7, 4, 3, 4, 4, 2, 2, 2, 4, 4, 3, 7, 3, 3, 2, 6, 3, 1, 2, 3, 1, 3, 2, 1, 3, 1, 1, 3, 1, 3, 2, 9, 5, 9, 10

Offset: 1

Author

Roger L. Bagula, Oct 01 2003

Keywords

• nonn
• look

Comments

A "commutator" between the Hofstadter A005185 sequence and the Conway-Hofstadter A004001 sequence.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..100000

Crossrefs

Cf. A004001, A005185, A284019 (compare the scatter plots).

Cf. also A286560.

Programs

Mathematica

Conway[n_Integer?Positive] := Conway[n] =Conway[Conway[n-1]] + Conway[n - Conway[n-1]] Conway[1] = Conway[2] = 1 Hofstadter[n_Integer?Positive] := Hofstadter[n] = Hofstadter[n - Hofstadter[n-1]] + Hofstadter[n - Hofstadter[n-2]] Hofstadter[1] = Hofstadter[2] = 1 digits=200 a=Table[1+Abs[Conway[Hofstadter[n]]-Hofstadter[Conway[n]]], {n, 1, digits}]

Scheme

(define (A087740 n) (+ 1 (abs (- (A004001 (A005185 n)) (A005185 (A004001 n)))))) ;; Scheme-code for A004001 and A005185 given under those entries.

Extensions

Data section extended to 120 terms by Antti Karttunen, May 22 2017