A177965 Indices m for which A177961(m) - m = 1.

1, 4, 7, 10, 16, 19, 22, 31, 34, 37, 40, 49, 52, 55, 64, 70, 76, 79, 82, 91, 97, 100, 106, 112, 115, 121, 136, 139, 142, 154, 157, 166, 169, 175, 184, 187, 190, 199, 205, 211, 217, 220, 229, 232, 244, 250, 262, 271, 274, 286, 289, 301, 304, 307, 310, 316, 322, 331, 337, 346

Offset: 1

Author

Vladimir Shevelev, May 16 2010

Keywords

• nonn

Comments

1 is the smallest value of |A177961(m) - m|.

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A002476, A177961, A177964, A177966.

Programs

Maple

1,op(map(t -> 3*t+1, select(t -> isprime(6*t+1),[$1..1000]))); # Robert Israel, Jul 31 2015

Mathematica

Position[Table[If[m == 1, 2, Mean[{FactorInteger[2 m - 1][[1, 1]], FactorInteger[2 m + 1][[1, 1]]}]] - m, {m, 346}], n_ /; n == 1] // Flatten (* Michael De Vlieger, Aug 02 2015 *)

Formula

a(n) = (A002476(n-1) + 1)/2, n > 1.

Extensions

More terms from R. J. Mathar, Oct 25 2010