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

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

Author

Clark Kimberling

Keywords

• nonn
• easy

Comments

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

Crossrefs

Cf. A026177, A026200.

Programs

PARI

\\ 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