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 A239237 Numbers n such that n^d_1 + n^d_2 + ... n^d_k is prime where d_i is the i-th digit in the decimal representation of n. 2
 10, 20, 203, 230, 308, 309, 330, 350, 503, 603, 650, 960, 1068, 1110, 1206, 1350, 1404, 1480, 1730, 1802, 1860, 1910, 2032, 2038, 2044, 2054, 2250, 2320, 2502, 3044, 3082, 3402, 3970, 4032, 4046, 4072, 4120, 4340, 4450, 4540, 4650, 4908, 5204, 5310, 5402 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The number must contain a 0 in its decimal representation. If not, the number is divisible by n. LINKS Giovanni Resta, Table of n, a(n) for n = 1..10000 EXAMPLE 20^2 + 20^0 = 401 is prime so 20 is a member of this sequence. 308^3 + 308^0 + 308^8 = 80985213602898040129 is prime so 308 is a member of this sequence. MATHEMATICA Select[Range[5000], PrimeQ@ Total[#^IntegerDigits[#]] &] (* Giovanni Resta, Mar 13 2014 *) PROG (Python) import sympy from sympy import isprime def PowOpp(x): ..if str(x).find('0') > -1: ....num = 0 ....for i in str(x): ......num += x**int(i) ....if isprime(num): ......return True x = 1 while x < 10**4: ..if PowOpp(x): ....print(x) ..x += 1 CROSSREFS Cf. A239236. Subsequence of A011540. Sequence in context: A250107 A038693 A217318 * A018990 A280882 A335802 Adjacent sequences:  A239234 A239235 A239236 * A239238 A239239 A239240 KEYWORD nonn,base AUTHOR Derek Orr, Mar 13 2014 STATUS approved

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Last modified December 5 11:05 EST 2021. Contains 349557 sequences. (Running on oeis4.)