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A258721
a(n) = 24*n^2 + 52*n + 29.
2
29, 105, 229, 401, 621, 889, 1205, 1569, 1981, 2441, 2949, 3505, 4109, 4761, 5461, 6209, 7005, 7849, 8741, 9681, 10669, 11705, 12789, 13921, 15101, 16329, 17605, 18929, 20301, 21721, 23189, 24705, 26269, 27881, 29541, 31249, 33005, 34809, 36661, 38561, 40509
OFFSET
0,1
COMMENTS
First differences of A079588.
6*a(n) - 5 is a square. Therefore, this is the quadrisection of the sequence which lists the numbers m such that 6*m-5 is a square (without 1): 1, 5, 9, 21, 29, 49, 61, 89, 105, 141, 161, 205, 229, ... . [Bruno Berselli, Jun 08 2015]
FORMULA
G.f.: (29 + 18*x + x^2)/(1 - x)^3.
MATHEMATICA
Table[24 n^2 + 52 n + 29, {n, 0, 50}] (* Bruno Berselli, Jun 08 2015 *)
PROG
(Haskell)
a258721 n = 4 * n * (6 * n + 13) + 29
(PARI) vector(50, n, n--; 24*n^2+52*n+29) \\ Bruno Berselli, Jun 08 2015
(Sage) [24*n^2+52*n+29 for n in (0..50)] # Bruno Berselli, Jun 08 2015
(Magma) [24*n^2+52*n+29: n in (0..50)] // Bruno Berselli, Jun 08 2015
(Maxima) makelist(24*n^2+52*n+29, n, 0, 50); /* Bruno Berselli, Jun 08 2015 */
CROSSREFS
Cf. A079588.
Sequence in context: A341550 A009435 A126554 * A009406 A211496 A233049
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Jun 08 2015
STATUS
approved