A094879 Where 1's occur in A094830 (nonprimes that reach a prime in one step under iteration of "x -> x + sum of squares of digits of x").

1, 10, 12, 14, 15, 16, 18, 34, 57, 74, 75, 78, 91, 94, 100, 102, 105, 108, 121, 122, 123, 126, 128, 140, 142, 146, 148, 160, 161, 165, 166, 168, 182, 183, 188, 213, 216, 217, 234, 275, 297, 301, 324, 327, 341, 387, 412, 413, 415, 418, 432, 450, 453, 455, 458

Offset

1,2

Links

Table of n, a(n) for n=1..55.

Mathematica

Select[Range[500], !PrimeQ[#]&&PrimeQ[#+Total[IntegerDigits[#]^2]]&] (* Harvey P. Dale, Mar 15 2015 *)

Crossrefs

Sequence in context: A350180 A099103 A208271 * A206286 A116023 A062408

Adjacent sequences: A094876 A094877 A094878 * A094880 A094881 A094882

Keyword

base,easy,nonn

Author

Jason Earls, Jun 15 2004

Status

approved