The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #8 Jun 20 2015 14:48:07
%S 26,31,58,71,89,107,112,116,157,161,193,211,247,310,337,395,458,490,
%T 503,535,580,584,620,688,769,778,841,850,859,868,872,877,895,949,985,
%U 989,1034,1070,1079,1102,1106,1133,1138,1142,1192,1201,1210,1214,1219,1232,1255,1277,1282,1295,1300,1327,1412,1493,1511,1538
%N Numbers n such that digital root of n is 4*(digital root of n-th prime).
%C Corresponding primes:
%C 101, 127, 271, 353, 461, 587, 613, 641, 919, 947, 1171, 1297, 1567, 2053, 2269, 2711, 3251, 3511, 3593, 3853, 4231, 4259, 4583, 5167, 5851, 5923, 6481, 6571, 6661, 6733, 6779, 6823, 6967, 7489, 7759, 7823, 8237, 8597, 8669, 8839, 8867, 9137, 9181, 9209, 9649, 9739, 9811, 9839, 9883.
%C Conjecture: a(n) ~ 27n. - _Charles R Greathouse IV_, Jun 18 2015
%t Reap[Do[If[FixedPoint[Total[IntegerDigits[#]]&,n]==4*Mod[Prime[n],9], Sow[{n,Prime[n]}]],{n,2000}]][[2,1]]
%o (PARI) n=0; forprime(p=2, 1e4, if(p%9*4==n++%9, print1(n", "))) \\ _Charles R Greathouse IV_, Jun 18 2015
%Y Cf. A010888, A038194, A258876, A258877, A259032, A259040.
%K nonn,base
%O 1,1
%A _Zak Seidov_, Jun 17 2015