A118592 Compound prime numbers. A prime is compound if its decimal digits can be divided into two contiguous subsets with equal sum.

11, 101, 167, 211, 257, 347, 431, 523, 541, 617, 743, 761, 853, 1423, 1427, 1607, 1753, 1973, 2011, 2213, 2237, 2341, 2417, 2543, 2617, 2671, 2819, 2837, 3137, 3407, 3461, 3517, 3571, 3719, 3847, 4013, 4127, 4211, 4217, 4637, 4673, 4691

Offset: 0

Author

Janos Lobb (janos(AT)lobb.com), May 17 2006

Keywords

• easy
• nonn
• base

Comments

Relates to the palindromic primes.

Examples

			40127 because 4+0+1+2=7
		

Crossrefs

Cf. A082435 and A083967.

Programs

Mathematica

First[Last[Reap[i = 1; mx = 10^4; While[i <= mx, pr = Prime[i]; prdig = IntegerDigits[pr]; prlen = Length[prdig]; j = 1; While[j < prlen, prLeft = Take[prdig, {1, j}]; prRight = Take[prdig, {j + 1, prlen}]; If[Total[prLeft] != Total[prRight], j++; Continue[], Sow[pr]; Break[]]; ]; i++; ]; ]]]