A191348 - OEIS

A191348

Array read by antidiagonals: ((ceiling(sqrt(n)) + sqrt(n))^k + (ceiling(sqrt(n)) - sqrt(n))^k)/2 for columns k >= 0 and rows n >= 0.

1, 0, 1, 0, 1, 1, 0, 2, 2, 1, 0, 4, 6, 2, 1, 0, 8, 20, 7, 2, 1, 0, 16, 68, 26, 8, 3, 1, 0, 32, 232, 97, 32, 14, 3, 1, 0, 64, 792, 362, 128, 72, 15, 3, 1, 0, 128, 2704, 1351, 512, 376, 81, 16, 3, 1, 0

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OFFSET

0,8

LINKS

Table of n, a(n) for n=0..55.

FORMULA

For each row n >= 0 let T(n,0)=1 and T(n,1) = ceiling(sqrt(n)), then for each column k >= 2: T(n,k) = T(n,k-2)*(n-T(n,1)^2) + T(n,k-1)*T(n,1)*2. - Charles L. Hohn, Aug 23 2019

EXAMPLE

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...

1, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, ...

1, 2, 6, 20, 68, 232, 792, 2704, 9232, 31520, 107616, ...

1, 2, 7, 26, 97, 362, 1351, 5042, 18817, 70226, 262087, ...

1, 2, 8, 32, 128, 512, 2048, 8192, 32768, 131072, 524288, ...

1, 3, 14, 72, 376, 1968, 10304, 53952, 282496, 1479168, 7745024, ...

1, 3, 15, 81, 441, 2403, 13095, 71361, 388881, 2119203, 11548575, ...

1, 3, 16, 90, 508, 2868, 16192, 91416, 516112, 2913840, 16450816, ...

1, 3, 17, 99, 577, 3363, 19601, 114243, 665857, 3880899, 22619537, ...

1, 3, 18, 108, 648, 3888, 23328, 139968, 839808, 5038848, 30233088, ...

1, 4, 26, 184, 1316, 9424, 67496, 483424, 3462416, 24798784, 177615776, ...

1, 4, 27, 196, 1433, 10484, 76707, 561236, 4106353, 30044644, 219825387, ...

1, 4, 28, 208, 1552, 11584, 86464, 645376, 4817152, 35955712, 268377088, ...

1, 4, 29, 220, 1673, 12724, 96773, 736012, 5597777, 42574180, 323800109, ...

1, 4, 30, 232, 1796, 13904, 107640, 833312, 6451216, 49943104, 386642400, ...

...

PROG

(PARI) T(n, k) = if (k==0, 1, if (k==1, ceil(sqrt(n)), T(n, k-2)*(n-T(n, 1)^2) + T(n, k-1)*T(n, 1)*2));

matrix(9, 9, n, k, T(n-1, k-1)) \\ Charles L. Hohn, Aug 23 2019

CROSSREFS

Row 1 is A000007, row 2 is A011782, row 3 is A006012, row 4 is A001075, row 5 is A081294, row 6 is A098648, row 7 is A084120, row 8 is A146963, row 9 is A001541, row 10 is A081341, row 11 is A084134, row 13 is A090965.

Row 3*2 is A056236, row 4*2 is A003500, row 5*2 is A155543, row 9*2 is A003499.

Cf. A191347 which uses floor() in place of ceiling().

Sequence in context: A229762 A062110 A122896 * A198792 A196182 A107267

Adjacent sequences: A191345 A191346 A191347 * A191349 A191350 A191351

KEYWORD

nonn,tabl

AUTHOR

Charles L. Hohn, May 31 2011

STATUS

approved