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A068896 Primes containing 2k digits in which the sum of the first k digits is that of the last k digits. 3
11, 1423, 1607, 1753, 1973, 2011, 2213, 2341, 2543, 2617, 2671, 2819, 2837, 3407, 3461, 3517, 3571, 3719, 3847, 4013, 4637, 4673, 4691, 4729, 4783, 4967, 5023, 5261, 5519, 5573, 5591, 5647, 5683, 5849, 5867, 6143, 6217, 6271, 6473, 6491, 6529, 6547, 7043, 7649, 7759, 8017, 8053, 8219, 8237, 8273, 8291, 8329, 8677, 9137, 9173, 9283, 9467 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

David A. Corneth, Table of n, a(n) for n = 1..10000

EXAMPLE

2341 is a member with 2+3 = 4+1.

MATHEMATICA

Select[Prime[Range[169, 1229]], Length[Union[Total/@TakeDrop[ IntegerDigits[ #], 2]]] == 1&] (* The program generates all 56 4-digit terms. To generate all 3669 of the 6-digit terms, change the Range constants to (9593, 78498) and change the 2 to 3. *) (* Harvey P. Dale, Aug 15 2021 *)

PROG

(Python)

from sympy import primerange

def sd(s): return sum(map(int, s))

def auptod(digits):

    alst = []

    for d in range(2, digits+1, 2):

        for p in primerange(10**(d-1), 10**d):

            s = str(p)

            if sd(s[:len(s)//2]) == sd(s[len(s)//2:]): alst.append(p)

    return alst

print(auptod(4)) # Michael S. Branicky, Aug 15 2021

CROSSREFS

Cf. A240927.

Sequence in context: A110195 A015484 A145185 * A286650 A015027 A160264

Adjacent sequences:  A068893 A068894 A068895 * A068897 A068898 A068899

KEYWORD

easy,nonn,base

AUTHOR

Amarnath Murthy, Mar 21 2002

EXTENSIONS

Corrected and extended by Harvey P. Dale, Aug 15 2021

11 prepended by David A. Corneth, Aug 15 2021

STATUS

approved

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Last modified October 7 16:02 EDT 2022. Contains 357275 sequences. (Running on oeis4.)