login
A054331
One eighth of eighth unsigned column of Lanczos triangle A053125.
2
1, 60, 1584, 27456, 366080, 4073472, 39690240, 349274112, 2835283968, 21554790400, 155194490880, 1067345510400, 7058711642112, 45127489814528, 280101660917760, 1693862087098368, 10009185060126720, 57935518230380544, 329171172648288256, 1839094001030922240, 10119502600794537984
OFFSET
0,2
REFERENCES
Cornelius Lanczos, Applied Analysis, Prentice-Hall, Englewood Cliffs, NJ, 1956, p. 518.
Theodore J. Rivlin, Chebyshev polynomials: from approximation theory to algebra and number theory, 2nd ed., Wiley, New York, 1990.
FORMULA
a(n) = 2^(2*n-3)*binomial(2*n+8, 7) = -A053125(n+7, 7)/8 = A054326(n)/8.
G.f.: (1+4*x)*(1+24*x+16*x^2)/(1-4*x)^8.
From Amiram Eldar, Oct 30 2025: (Start)
Sum_{n>=0} 1/a(n) = 165144/5 + 81760*log(2) - 81648*log(3).
Sum_{n>=0} (-1)^n/a(n) = -37464/5 + 9856*arctan(1/2) + 13104*log(5/4). (End)
MATHEMATICA
Table[4^n Binomial[2n+8, 7]/8, {n, 0, 20}] (* Harvey P. Dale, Nov 03 2011 *)
LinearRecurrence[{32, -448, 3584, -17920, 57344, -114688, 131072, -65536}, {1, 60, 1584, 27456, 366080, 4073472, 39690240, 349274112}, 20] (* Harvey P. Dale, Feb 25 2022 *)
PROG
(PARI) vector(20, n, n--; 2^(2*n-3)*binomial(2*n+8, 7)) \\ G. C. Greubel, Jul 22 2019
(Magma) [2^(2*n-3)*Binomial(2*n+8, 7): n in [0..20]]; // G. C. Greubel, Jul 22 2019
(SageMath) [2^(2*n-3)*binomial(2*n+8, 7) for n in (0..20)] # G. C. Greubel, Jul 22 2019
(GAP) List([0..20], n-> 2^(2*n-3)*Binomial(2*n+8, 7)); # G. C. Greubel, Jul 22 2019
CROSSREFS
Sequence in context: A269196 A379607 A393526 * A160349 A281373 A053528
KEYWORD
easy,nice,nonn
STATUS
approved