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

0,1

Comments

Relates to the palindromic primes.

Links

Table of n, a(n) for n=0..41.

Example

40127 because 4+0+1+2=7

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++; ]; ]]]

Crossrefs

Cf. A082435 and A083967.

Sequence in context: A058411 A134462 A156753 * A156617 A168536 A089716

Adjacent sequences: A118589 A118590 A118591 * A118593 A118594 A118595

Keyword

easy,nonn,base

Author

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

Status

approved