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A290538
Let S be the sequence generated by these rules: 0 is in S, and if z is in S, then z + 1 and z * (1+i) are in S (where i denotes the imaginary unit), and duplicates are deleted as they occur; a(n) = the square of the norm of the n-th term of S.
4
0, 1, 4, 2, 9, 8, 5, 4, 16, 18, 13, 16, 10, 10, 5, 8, 25, 32, 25, 36, 20, 26, 17, 32, 17, 20, 13, 20, 10, 5, 16, 36, 50, 41, 64, 34, 50, 37, 72, 29, 40, 29, 52, 34, 25, 64, 26, 34, 25, 40, 26, 17, 40, 9, 20, 10, 9, 32, 49, 72, 61, 100, 52, 82, 65, 128, 45, 68
OFFSET
1,3
COMMENTS
See A290536 for the real part of the n-th term of S and additional comments.
See A290537 for the imaginary part of the n-th term of S.
a(n) tends to infinity as n tends to infinity.
LINKS
FORMULA
a(n) = A290536(n)^2 + A290537(n)^2.
EXAMPLE
S(1) = 0 by definition; so a(1) = 0.
S(1)+1 = 1 has not yet occurred; so S(2) = 1 and a(2) = 1.
S(1)*(i+i) = 0 has already occurred.
S(2)+1 = 2 has not yet occurred; so S(3) = 2 and a(3) = 4.
S(2)*(1+i) = 1+i has not yet occured; so S(4) = 1+i and a(4) = 2.
S(3)+1 = 3 has not yet occurred; so S(5) = 3 and a(5) = 9.
PROG
(PARI) See Links section.
CROSSREFS
Sequence in context: A278103 A249327 A182728 * A097664 A144811 A185654
KEYWORD
nonn,look
AUTHOR
Rémy Sigrist, Aug 05 2017
STATUS
approved