A258877 Primes p=prime(m) such that both p and m have the same digital root.

97, 131, 199, 263, 349, 457, 479, 521, 541, 617, 661, 733, 829, 839, 881, 1039, 1049, 1091, 1103, 1277, 1289, 1301, 1361, 1433, 1487, 1499, 1549, 1571, 1759, 1913, 1933, 1993, 2089, 2099, 2129, 2141, 2221, 2273, 2357, 2377, 2389, 2441

Offset: 1

Author

Zak Seidov, Jun 13 2015

Keywords

• nonn
• base

Examples

			Both 97 = prime(25) and 25 have digital root = 7,
both 131 = prime(32) and 32 have digital root = 5.
		

Crossrefs

Cf. A000040, A010888, A038194, A258876.

Programs

Mathematica

Reap[Do[If[FixedPoint[Total[IntegerDigits[#]]&,n]==Mod[(p=Prime[n]),9],Sow[p]],{n,439}]][[2,1]]
Prime[Select[Range@370,Mod[#,9]==Mod[Prime[#],9]&]] (* Ivan N. Ianakiev, Jun 18 2015 *)

Formula

a(n) = A000040(A258876(n)).