A027696 - OEIS

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

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A027696

Nonparametric solutions to problem in A027669: n such that for some m, the sum of the first m n-gonal numbers is again an n-gonal number.

1

3, 4, 6, 8, 10, 11, 14, 17, 30, 41, 43, 50, 60, 88, 145, 276, 322, 374, 823, 1152

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,1

LINKS

Table of n, a(n) for n=0..19.

FORMULA

The parametric solution: if n=2 mod 3, the sum of the first (n^2-4*n-2)/3 n-gonal numbers is the ((n^3-6*n^2+3*n+19)/9)-th n-gonal number.

CROSSREFS

Sequence in context: A184398 A024665 A027669 * A027440 A360637 A169866

Adjacent sequences: A027693 A027694 A027695 * A027697 A027698 A027699

KEYWORD

nonn,more

AUTHOR

Masanobu Kaneko (mkaneko(AT)math.kyushu-u.ac.jp)

EXTENSIONS

More terms from Masanobu Kaneko (mkaneko(AT)math.kyushu-u.ac.jp), Jan 05 1998

STATUS

approved