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A282232
a(n) = ((3*n + 1)^6 - 1)/9.
0
0, 455, 13072, 111111, 536312, 1864135, 5227320, 12597767, 27126736, 53543367, 98611520, 171644935, 285080712, 455111111, 702373672, 1052699655, 1537920800, 2196734407, 3075626736, 4229854727, 5724486040, 7635497415, 10050931352, 13072111111, 16814914032, 21411103175, 27009717280
OFFSET
0,2
COMMENTS
If n is in the sequence, then so is n followed by q ones, where q is congruent to 0 mod 6. For example, 13072 is a term, so 13072111111 is also.
EXAMPLE
a(2) =81*2^6 + 162*2^5 + 135*2^4 + 60*2^3 + 15*2^2 + 2*2 = 13072.
MAPLE
f:=n->((3*n+1)^6-1)/9; [seq(f(n), n=0..30)];
CROSSREFS
Sequence in context: A260735 A241618 A251337 * A061544 A015276 A145528
KEYWORD
nonn,easy
AUTHOR
Jake Lawrence, Mar 05 2017
EXTENSIONS
Edited by N. J. A. Sloane, Mar 07 2017
STATUS
approved