A028319 Distinct odd elements in the 5-Pascal triangle A028313.

1, 5, 7, 19, 9, 27, 65, 11, 101, 57, 147, 231, 13, 69, 273, 15, 355, 855, 111, 451, 2277, 17, 127, 1661, 3487, 5379, 689, 2223, 11583, 833, 7371, 20449, 181, 995, 3745, 10283, 21385, 34463, 43615, 21, 201, 1377, 23, 1599, 7293, 267, 1843, 31977, 25

Offset: 0

Author

Mohammad K. Azarian

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A028313, A028314, A028315, A028316, A028317, A028318, A028320.

Cf. A028321, A028322, A028323, A028324, A028325, A051472.

Programs

Mathematica

DeleteDuplicates[Table[If[n<2, 1, Binomial[n,k] +3*Binomial[n-2,k-1]], {n,0,30}, {k,0,n}]//Flatten]//Select[OddQ] (* G. C. Greubel, Jul 13 2024 *)

SageMath

def A028323(n, k): return 1 if n<2 else binomial(n, k) + 3*binomial(n-2, k-1)
b=flatten([[A028323(n, k) for k in range(n+1)] for n in range(31)])
def a(seq): # order preserving
    nd = [] # no duplicates
    [nd.append(i) for i in seq if not nd.count(i) and i%2==1]
    return nd
a(b) # A028319 # G. C. Greubel, Jul 13 2024

Extensions

More terms from James Sellers, Dec 08 1999