

A016161


Expansion of 1/((15x)(17x)).


5



1, 12, 109, 888, 6841, 51012, 372709, 2687088, 19200241, 136354812, 964249309, 6798573288, 47834153641, 336059778612, 2358521965909, 16540171339488, 115933787267041, 812299450322412, 5689910849522509
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OFFSET

0,2


COMMENTS

Also, this is the number of incongruent integeredged Heron triangles whose circumdiameter is the product of n distinct primes each of shape 4k + 1. Cf. A003462, A109021.  R. K. Guy, Jan 31 2007


LINKS

Table of n, a(n) for n=0..18.
Index entries for linear recurrences with constant coefficients, signature (12,35).


FORMULA

a(n) = (7^(n+1)5^(n+1))/2 = A081200(n+1). Binomial transform of A080962.  R. J. Mathar, Sep 18 2008
a(n) = 7*a(n1) + 5^n.  Vincenzo Librandi, Feb 09 2011


PROG

(PARI) Vec(1/((15*x)*(17*x))+O(x^99)) \\ Charles R Greathouse IV, Sep 24 2012


CROSSREFS

Sequence in context: A011999 A128877 A085797 * A081200 A016214 A037581
Adjacent sequences: A016158 A016159 A016160 * A016162 A016163 A016164


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane


STATUS

approved



