A234021 -id:A234021 - cp's OEIS frontend

A108662 Numbers whose sum of squares of digits is a prime.

11, 12, 14, 16, 21, 23, 25, 27, 32, 38, 41, 45, 49, 52, 54, 56, 58, 61, 65, 72, 78, 83, 85, 87, 94, 101, 102, 104, 106, 110, 111, 113, 119, 120, 126, 131, 133, 137, 140, 146, 159, 160, 162, 164, 166, 168, 173, 179, 186, 191, 195, 197, 199, 201, 203, 205, 207, 210

Offset: 1

Zak Seidov, Jun 16 2005

If m is in the sequence, then so are 10*m and any anagram (even with adding zeros between digits) of m. E.g., 12 is a term, hence 21, 102, 120, 201, 10020 all are here.

A sequence of primitive terms is of interest. It starts with 11, 12, 14, 16, 23, 25, 27, 38, 45, 49, 56, 58, 78, 111, 113, 119, 126, 133, 137, 146, 159, 166, 168, 179, 199. Note that digits are in nondecreasing order. - Zak Seidov, Dec 31 2013

			23 is in the sequence because 2^2 + 3^2 = 13 is a prime.

Harvey Dale and Zak Seidov, Table of n, a(n) for n = 1..10000 [First 1000 terms from Harvey Dale]

Cf. A003132, A009994, A052034, A234021.

Select[Range[300],PrimeQ[Total[IntegerDigits[#]^2]]&] (* Harvey P. Dale, May 25 2012 *)

isok(n) = isprime(norml2(digits(n))); \\ Michel Marcus, Jan 09 2019

cp's OEIS Frontend

A108662 Numbers whose sum of squares of digits is a prime.

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