The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A252359 Numbers n such that the sum of the heptagonal numbers H(n) and H(n+1) is equal to the pentagonal number P(m) for some m. 2
 158, 76252, 36753402, 17715063608, 8538623905750, 4115599007507988, 1983710182994944562, 956144192604555770992, 460859517125212886673678, 222133331110160006820941900, 107067804735579998074807322218, 51606459749218448912050308367272 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Also positive integers x in the solutions to 10*x^2-3*y^2+4*x+y+2 = 0, the corresponding values of y being A252360. LINKS Colin Barker, Table of n, a(n) for n = 1..372 Index entries for linear recurrences with constant coefficients, signature (483,-483,1). FORMULA a(n) = 483*a(n-1)-483*a(n-2)+a(n-3). G.f.: 2*x*(31*x-79) / ((x-1)*(x^2-482*x+1)). a(n) = (-24+(12-5*sqrt(30))*(241+44*sqrt(30))^(-n)+(12+5*sqrt(30))*(241+44*sqrt(30))^n)/120. - Colin Barker, Apr 26 2016 EXAMPLE 158 is in the sequence because H(158)+H(159) = 62173+62964 = 125137 = P(289). PROG (PARI) Vec(2*x*(31*x-79)/((x-1)*(x^2-482*x+1)) + O(x^100)) CROSSREFS Cf. A000326, A000566, A252360. Sequence in context: A180096 A250996 A280483 * A159418 A159434 A287798 Adjacent sequences:  A252356 A252357 A252358 * A252360 A252361 A252362 KEYWORD nonn,easy AUTHOR Colin Barker, Dec 17 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 16 07:50 EDT 2022. Contains 356160 sequences. (Running on oeis4.)