A026200 -id:A026200 - cp's OEIS frontend

A026201 Position of n in A026200.

1, 2, 5, 3, 9, 4, 13, 6, 17, 7, 21, 8, 25, 10, 29, 11, 33, 12, 37, 14, 41, 15, 45, 16, 49, 18, 53, 19, 57, 20, 61, 22, 65, 23, 69, 24, 73, 26, 77, 27, 81, 28, 85, 30, 89, 31, 93, 32, 97, 34, 101, 35, 105, 36, 109, 38, 113, 39, 117, 40, 121

Offset: 1

Clark Kimberling

nonn

Conjectures from Colin Barker, Oct 14 2019: (Start)
G.f.: x*(1 + 2*x + 4*x^2 + x^3 + 4*x^4 + x^5 + 3*x^6) / ((1 - x)^2*(1 + x)^2*(1 - x + x^2)*(1 + x + x^2)).
a(n) = a(n-2) + a(n-6) - a(n-8) for n>8.
(End)

A026218 a(n) = (1/3)*(s(n) + 2), where s(n) is the n-th number congruent to 1 mod 3 in A026177.

Original entry on oeis.org

1, 2, 4, 6, 3, 8, 10, 12, 5, 14, 16, 18, 7, 20, 22, 24, 9, 26, 28, 30, 11, 32, 34, 36, 13, 38, 40, 42, 15, 44, 46, 48, 17, 50, 52, 54, 19, 56, 58, 60, 21, 62, 64, 66, 23, 68, 70, 72, 25, 74, 76, 78, 27, 80, 82, 84, 29, 86, 88, 90, 31, 92, 94

Offset: 1

Clark Kimberling

This seems to be the same as A026200. - Colin Barker, Oct 15 2019

Cf. A026177, A026200.

\\ here S is A026177 as vector.
S(n)={my(a=vector(n)); a[1]=1; for(i=2, 2*n, my(h=i\2); if(i%2==0&&!a[i-h], a[i-h]=i, if(i+h<=n, a[i+h]=i))); a}
{[(k + 2)/3 | k<-S(500), k%3==1]} \\ Andrew Howroyd, Oct 15 2019

cp's OEIS Frontend

A026201 Position of n in A026200.

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A026218 a(n) = (1/3)*(s(n) + 2), where s(n) is the n-th number congruent to 1 mod 3 in A026177.

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