A230414 Inverse function for injection A219650.

0, 1, 2, 0, 0, 3, 4, 5, 0, 0, 6, 7, 8, 0, 0, 9, 10, 11, 0, 0, 0, 0, 0, 12, 13, 14, 0, 0, 15, 16, 17, 0, 0, 18, 19, 20, 0, 0, 21, 22, 23, 0, 0, 0, 0, 0, 24, 25, 26, 0, 0, 27, 28, 29, 0, 0, 30, 31, 32, 0, 0, 33, 34, 35, 0, 0, 0, 0, 0, 36, 37, 38, 0, 0, 39, 40, 41

Offset: 0

Author

Antti Karttunen, Oct 31 2013

Keywords

• nonn

Comments

a(0)=0; thereafter if n occurs as a term of A219650, a(n)=its position in A219650, otherwise zero. This works as an "inverse" function for A219650 in a sense that a(A219650(n)) = n for all n.

Links

• Antti Karttunen, Table of n, a(n) for n = 0..10079

Crossrefs

Cf. A219650, A230423, A230424. A219658 gives the positions of zeros after the first one. Analogous sequence for binary system: A213714.

Programs

Scheme

(define (A230414 n) (* (A230412 n) (A230413 n)))

Formula

a(n) = A230412(n) * A230413(n).

a(n) = A230423(n)/2.