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A128511
Numbers which are both lucky and pentagonal.
3
1, 51, 477, 651, 925, 2625, 5551, 6501, 9801, 17767, 20475, 25285, 26467, 29751, 39285, 45327, 67947, 75825, 84135, 84847, 95887, 99717, 102051, 114955, 135751, 151527, 154401, 178365, 245835, 261877, 272001, 275847, 287547, 292825, 307587
OFFSET
1,2
COMMENTS
Second row of array T(k,n) = n-th Lucky number which is also a (k+3)-gonal number, for nonnegative k, whose zeroth and first rows are: A118565 Numbers which are both lucky and triangular. A031162 Numbers that are both lucky and square.
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..1244 (terms < 10^9)
FORMULA
A000959 INTERSECTION A000326 = A000959 INTERSECTION {n*(3*n-1)/2}.
EXAMPLE
a(2) = 51 = A000959(14) = A000326(6).
a(3) = 477 = A000959(81) = A000326(18).
MAPLE
isA000326 := proc(n) local di ; if issqr(1+24*n) or n =0 then di := 1+sqrt(1+24*n); if di mod 6 = 0 or n = 0 then true ; else false ; fi ; else false ; fi; end: lin := fscanf("b000959.txt", "%d %d") : while lin <> [] do a := op(2, lin) ; if isA000326( a ) then printf("%d, ", a) ; fi ; lin := fscanf("b000959.txt", "%d %d") ; od : # R. J. Mathar, May 13 2007
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, May 07 2007
EXTENSIONS
More terms from R. J. Mathar, May 13 2007
STATUS
approved