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A179549 Primes p such that p minus the sum of the square of its digits yields a prime. 4
13, 53, 127, 233, 257, 293, 457, 521, 541, 547, 587, 857, 983, 1151, 1153, 1429, 1481, 1489, 1511, 1553, 1559, 1579, 1621, 1753, 1861, 2099, 2129, 2143, 2239, 2273, 2341, 2347, 2383, 2411, 2417, 2459, 2549, 2657, 2677, 2729, 2741, 2789, 2837, 2897, 2927 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This sequence differs from A076163 which takes the absolute value of the difference.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

a(5)=257 since 257-(2^2+5^2+7^2)=179 is a prime.

MATHEMATICA

ssdQ[n_]:=Module[{c=n-Total[IntegerDigits[n]^2]}, Positive[c]&&PrimeQ[c]]; Select[Prime[Range[500]], ssdQ] (* Harvey P. Dale, Dec 26 2018 *)

PROG

(PARI) isok(n) = {if (isprime(n), digs = digits(n, 10); isprime(n - sum(i=1, #digs, digs[i]^2)); , 0)} \\ Michel Marcus, Jul 18 2013

CROSSREFS

Cf. A076162, A076163.

Sequence in context: A228872 A041322 A022284 * A139974 A142188 A248409

Adjacent sequences:  A179546 A179547 A179548 * A179550 A179551 A179552

KEYWORD

nonn,base

AUTHOR

Carmine Suriano, Jul 19 2010

EXTENSIONS

A-number typo and signs in the example corrected - R. J. Mathar, Oct 23 2010

STATUS

approved

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Last modified August 3 17:04 EDT 2021. Contains 346439 sequences. (Running on oeis4.)