A354200 - OEIS

A354200

Prime map that sends 2 to 5, and each 4k+1 and 4k+3 prime to the next larger prime of the same type.

5, 7, 13, 11, 19, 17, 29, 23, 31, 37, 43, 41, 53, 47, 59, 61, 67, 73, 71, 79, 89, 83, 103, 97, 101, 109, 107, 127, 113, 137, 131, 139, 149, 151, 157, 163, 173, 167, 179, 181, 191, 193, 199, 197, 229, 211, 223, 227, 239, 233, 241, 251, 257, 263, 269, 271, 277, 283, 281, 293, 307, 313, 311, 331, 317, 337, 347, 349, 359

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..69.

FORMULA

For all n >= 1, A354201(A000720(a(n))) = A000040(n).

EXAMPLE

A000040(2) = 3, and the next larger prime of the form 4k+3 is 7, therefore a(2) = 7.

A000040(3) = 5, and the next larger prime of the form 4k+1 is 13, therefore a(3) = 13.

A000040(4) = 7, and the next larger prime of the form 4k+3 is 11, therefore a(4) = 11.

PROG

(PARI) A354200(n) = if(1==n, 5, my(p=prime(n), m=p%4); forprime(q=1+p, , if(m==(q%4), return(q))));

CROSSREFS

Cf. A000040, A000720, A354201, A354202.

Sequence in context: A255233 A361708 A074755 * A002659 A357938 A164122

Adjacent sequences: A354197 A354198 A354199 * A354201 A354202 A354203

KEYWORD

nonn

AUTHOR

Antti Karttunen, May 23 2022

STATUS

approved