

A276574


The infinite trunk of least squares beanstalk with reversed subsections.


7



0, 3, 8, 6, 15, 11, 24, 21, 18, 16, 35, 32, 30, 27, 48, 45, 43, 40, 38, 63, 59, 56, 53, 51, 80, 78, 75, 72, 70, 67, 64, 99, 96, 93, 90, 88, 85, 83, 120, 117, 115, 112, 108, 105, 102, 143, 139, 136, 134, 131, 128, 126, 123, 168, 165, 162, 160, 158, 155, 152, 149, 147, 144, 195, 192, 189, 186, 183, 179, 176, 173, 171
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OFFSET

0,2


LINKS



FORMULA

a(0) = 0; a(1) = 3; for n > 1, let k = A255131(a(n1)). If k+1 is not a square, then a(n) = k, otherwise a(n) = A000290(2+A000196(k+1))  1.


EXAMPLE

This can be viewed as an irregular table, where after 0, each row has A260734(n) = 1, 2, 2, 4, 4, 5, 5, 7, ... terms:
0;
3;
8, 6;
15, 11;
24, 21, 18, 16;
35, 32, 30, 27;
48, 45, 43, 40, 38;
63, 59, 56, 53, 51;
80, 78, 75, 72, 70, 67, 64;
99, 96, 93, 90, 88, 85, 83;
120, 117, 115, 112, 108, 105, 102;
...
Each row begins with (n^2)1 (see A005563), and each successive term is obtained by subtracting A002828(k) from the previous term k, until ((n1)^2)1 would be encountered, which is not listed second time (as it already occurs as the first term of the previous row), but instead, the current row is finished and the next row is started with the term ((n+1)^2)1.


PROG

(Scheme)
(definec (A276574 n) (cond ((zero? n) n) ((= 1 n) 3) (else (let ((maybe_next (A255131 (A276574 ( n 1))))) (if (zero? (A010052 (+ 1 maybe_next))) maybe_next (+ 1 (A000290 (+ 2 (A000196 (+ 1 maybe_next))))))))))


CROSSREFS



KEYWORD

nonn,tabf


AUTHOR



EXTENSIONS

Example section added and the formula rewritten to a simpler form (which is now correct)  Antti Karttunen, Oct 16 2016


STATUS

approved



