A354201 Inverse prime map of A354200.

1, 1, 2, 3, 7, 5, 13, 11, 19, 17, 23, 29, 37, 31, 43, 41, 47, 53, 59, 67, 61, 71, 79, 73, 89, 97, 83, 103, 101, 109, 107, 127, 113, 131, 137, 139, 149, 151, 163, 157, 167, 173, 179, 181, 193, 191, 199, 211, 223, 197, 229, 227, 233, 239, 241, 251, 257, 263, 269, 277, 271, 281, 283, 307, 293, 313, 311, 317, 331, 337

Offset: 1

Author

Antti Karttunen, May 23 2022

Keywords

• nonn

Crossrefs

Cf. A000040, A000720, A354200, A354203.

Programs

PARI

A354201(n) = if(n<=3,(n+1)\2,my(m=prime(n)%4); forstep(i=n-1,0,-1,if(m==(prime(i)%4),return(prime(i)))));

Formula

For all n >= 1, a(A000720(A354200(n))) = A000040(n).