This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A176496 Sum_{k=1..n} 2^nonprime(k). 0
 2, 18, 82, 338, 850, 1874, 5970, 22354, 55122, 120658, 382802, 1431378, 3528530, 7722834, 24500050, 58054482, 125163346, 259381074, 527816530, 1601558354 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA a(1) = 2 ; a(n) = a(n-1) + 2^A018252(n) EXAMPLE a(2) = 2 + 2^A018252(2) = 2 + 2^4 = 18 ; a(3) = 18 + 2^A018252(3) = 18 + 2^6 = 82. PROG (PARI) a(n) = s = 0; k = 1; while(n, if(!isprime(k), s += 2^k; n--); k++); return(s) CROSSREFS Cf. A076793, A018252 Sequence in context: A056664 A213830 A064057 * A091940 A068605 A070171 Adjacent sequences:  A176493 A176494 A176495 * A176497 A176498 A176499 KEYWORD easy,nonn AUTHOR David Lazar (lazar6(AT)illinois.edu), Apr 19 2010 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.