The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A370291 Triangular number T(n) = A000217(n) occurs C(n) = A000108(n) times. 2
 0, 1, 3, 3, 6, 6, 6, 6, 6, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 21, 21, 21, 21, 21 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Paolo Xausa, Table of n, a(n) for n = 0..10000 FORMULA a(n) = A000217(A072643(n)). Sum_{n>=1} (-1)^(n+1)/a(n) = Sum_{n>=1} (-1/2)^(n-1)/(2^n-1) = 0.86233289403022175171... . - Amiram Eldar, Feb 17 2024 EXAMPLE Written as a triangle: 0; 1; 3, 3; 6, 6, 6, 6, 6; 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10; ... MAPLE T:= n-> n*(n+1)/2\$binomial(2*n, n)/(n+1): seq(T(n), n=0..5); # Alois P. Heinz, Feb 16 2024 MATHEMATICA Flatten[Array[Table[PolygonalNumber[#], CatalanNumber[#]] &, 7, 0]] CROSSREFS Cf. A000108, A000217, A072643. Row sums of A370221 (for n >= 1). Row sums as triangle give A002457(n-1) for n>=1. Sequence in context: A342511 A175520 A271668 * A072464 A262871 A160745 Adjacent sequences: A370288 A370289 A370290 * A370292 A370293 A370294 KEYWORD nonn,easy,tabf AUTHOR Paolo Xausa, Feb 14 2024 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 June 17 07:23 EDT 2024. Contains 373433 sequences. (Running on oeis4.)