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A052034 Primes such that the sum of the squares of their digits is also a prime. 17
11, 23, 41, 61, 83, 101, 113, 131, 137, 173, 179, 191, 197, 199, 223, 229, 311, 313, 317, 331, 337, 353, 373, 379, 397, 401, 409, 443, 449, 461, 463, 467, 601, 641, 643, 647, 661, 683, 719, 733, 739, 773, 797, 829, 863, 883, 911, 919, 937, 971, 977, 991, 997, 1013 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes p such that the sum of the squared digits of p is a prime q. For the values of q see A109181.

REFERENCES

Charles W. Trigg, Journal of Recreational Mathematics, Vol. 20(2), 1988.

"Hands On Numbers Count", Personal Computer World, 1997, p. 290.

Clifford A. Pickover, A Passion for Mathematics, John Wiley & Sons, Inc., 2005, p. 89.

LINKS

Zak Seidov, Table of n, a(n) for n = 1..10000

EXAMPLE

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

9431 -> 9^2 + 4^2 + 3^2 + 1^2 = 107 (which is prime).

MAPLE

a:=proc(n) local nn, L: nn:=convert(n, base, 10): L:=nops(nn): if isprime(n)= true and isprime(add(nn[j]^2, j=1..L))=true then n else end if end proc: seq(a(n), n=1..1000); # Emeric Deutsch, Jan 08 2008

MATHEMATICA

Select[Prime[Range[250]], PrimeQ[Total[IntegerDigits[#]^2]]&]  (* Harvey P. Dale, Dec 19 2010 *)

CROSSREFS

Cf. A003132, A052035, A108662, A109181.

Sequence in context: A094376 A086524 A060915 * A077041 A190797 A068842

Adjacent sequences:  A052031 A052032 A052033 * A052035 A052036 A052037

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Dec 15 1999

EXTENSIONS

Edited by N. J. A. Sloane, Dec 15 2007 and again on Dec 05 2008 at the suggestion of Zak Seidov

STATUS

approved

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Last modified July 15 22:48 EDT 2019. Contains 325061 sequences. (Running on oeis4.)