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A195028 a(n) = n*(14*n + 13). 2
0, 27, 82, 165, 276, 415, 582, 777, 1000, 1251, 1530, 1837, 2172, 2535, 2926, 3345, 3792, 4267, 4770, 5301, 5860, 6447, 7062, 7705, 8376, 9075, 9802, 10557, 11340, 12151, 12990, 13857, 14752, 15675, 16626, 17605, 18612, 19647, 20710, 21801, 22920 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Sequence found by reading the line from 0, in the direction 0, 27, ..., in the Pythagorean spiral whose edges have length A195019 and whose vertices are the numbers A195020. Numbers opposite to the semi-diagonal A195024 in the same square spiral, which is related to the primitive Pythagorean triple [3, 4, 5].

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

a(n) = 14*n^2 + 13*n.

G.f.: x*(27+x)/(1-x)^3. - Colin Barker, Jan 09 2012

PROG

(MAGMA) [14*n^2 +13*n: n in [0..50]]; // Vincenzo Librandi, Oct 14 2011

(PARI) a(n)=n*(14*n+13) \\ Charles R Greathouse IV, Jun 17 2017

CROSSREFS

Cf. A144555, A152760, A195019, A195020, A195021, A195023, A195024, A195025, A195026, A195027, A195320, A185019, A193053, A198017.

Sequence in context: A045004 A042432 A042430 * A042434 A042436 A042438

Adjacent sequences:  A195025 A195026 A195027 * A195029 A195030 A195031

KEYWORD

nonn,easy

AUTHOR

Omar E. Pol, Oct 13 2011

EXTENSIONS

Name suggested by Bruno Berselli, Oct 13 2011

STATUS

approved

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Last modified August 2 07:42 EDT 2021. Contains 346411 sequences. (Running on oeis4.)