A234017 Inverse function for injection A055938.

0, 0, 1, 0, 0, 2, 3, 0, 0, 4, 0, 0, 5, 6, 7, 0, 0, 8, 0, 0, 9, 10, 0, 0, 11, 0, 0, 12, 13, 14, 15, 0, 0, 16, 0, 0, 17, 18, 0, 0, 19, 0, 0, 20, 21, 22, 0, 0, 23, 0, 0, 24, 25, 0, 0, 26, 0, 0, 27, 28, 29, 30, 31, 0, 0, 32, 0, 0, 33, 34, 0, 0, 35, 0, 0, 36, 37, 38

Offset: 0

Author

Antti Karttunen, Dec 18 2013

Keywords

• nonn

Comments

a(0)=0; thereafter if n occurs as a term of A055938, a(n)=its position in A055938, otherwise zero. This works as an "inverse" function for A055938 in a sense that a(A055938(n)) = n for all n.

a(n)*A213714(n) = 0 for all n.

Links

• Antti Karttunen, Table of n, a(n) for n = 0..8191
• Indranil Ghosh, Python program to generate the sequence

Crossrefs

Cf. also A079559, A234016, A055938, A213714, A233275, A233277.

Programs

Scheme

(define (A234017 n) (* (- 1 (A079559 n)) (A234016 n)))

Formula

a(n) = (1-A079559(n)) * A234016(n).