|
|
A139607
|
|
a(n) = 21*n + 7.
|
|
3
|
|
|
7, 28, 49, 70, 91, 112, 133, 154, 175, 196, 217, 238, 259, 280, 301, 322, 343, 364, 385, 406, 427, 448, 469, 490, 511, 532, 553, 574, 595, 616, 637, 658, 679, 700, 721, 742, 763, 784, 805, 826, 847, 868, 889, 910, 931, 952, 973, 994
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,1
|
|
COMMENTS
|
Numbers of the 7th column of positive numbers in the square array of nonnegative and polygonal numbers A139600.
7th transversal numbers (or 7-transversal numbers): (A000217(7)-7)*n + 7.
|
|
REFERENCES
|
A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 189. - From N. J. A. Sloane, Dec 01 2012
|
|
LINKS
|
|
|
FORMULA
|
E.g.f.: 7*exp(x)*(1 + 3*x).
a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)
|
|
MATHEMATICA
|
21*Range[0, 50]+7 (* or *) LinearRecurrence[{2, -1}, {7, 28}, 50] (* Harvey P. Dale, Feb 23 2020 *)
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|