login
A230414
Inverse function for injection A219650.
7
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
0,3
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
FORMULA
a(n) = A230412(n) * A230413(n).
a(n) = A230423(n)/2.
PROG
(Scheme)
(define (A230414 n) (* (A230412 n) (A230413 n)))
CROSSREFS
Cf. A219650, A230423, A230424. A219658 gives the positions of zeros after the first one. Analogous sequence for binary system: A213714.
Sequence in context: A188430 A013585 A261319 * A053653 A332629 A262174
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 31 2013
STATUS
approved