cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A084195 Even numbers n such that the sum of the digits is prime, n/2 is prime and the sum of the digits of n/2 is also prime.

Original entry on oeis.org

14, 58, 94, 122, 166, 274, 278, 302, 346, 382, 386, 454, 458, 526, 562, 566, 634, 674, 706, 746, 818, 922, 926, 1114, 1154, 1198, 1202, 1282, 1286, 1466, 1514, 1594, 1642, 1646, 1774, 1822, 1954, 2038, 2078, 2102, 2182, 2186, 2218, 2258, 2326, 2362
Offset: 1

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Author

Patrick Capelle, Jun 20 2003

Keywords

Examples

			5+8=13 for n=58 and 2+9=11 for n/2=29=prime.
1+2+2=5 for n=122 and 6+1=7 for n/2=61=prime.
2+7+8=17 for n=278 and 1+3+9=13 for n/2=139=prime.
		

Crossrefs

Subsequence of A084194.

Programs

  • PARI
    isok(n) = {if (n % 2, return (0)); dn = digits(n); dh = digits(n/2); isprime(n/2) && isprime(sum(i=1, #dn, dn[i])) && isprime(sum(i=1, #dh, dh[i]));} \\ Michel Marcus, Aug 12 2013

Extensions

More terms from Michel Marcus, Aug 12 2013