A114944 -id:A114944 - cp's OEIS frontend

A114966 Prime(n) + Semiprime(n) + 3AlmostPrime(n) + 4AlmostPrime(n) + 5AlmostPrime(n).

62, 93, 140, 157, 214, 224, 248, 326, 344, 364, 384, 423, 451, 516, 538, 568, 589, 600, 630, 672, 689, 736, 807, 837, 871, 892, 916, 937, 964, 993, 1030, 1052, 1090, 1100, 1164, 1192, 1250, 1294, 1320, 1359, 1373, 1387, 1435, 1454, 1487, 1526, 1547, 1584

Offset: 1

Jonathan Vos Post, Feb 21 2006

Primes in this sequence include a(4) = 157, a(28) = 937, a(41) = 1373, a(45) = 1487, a(49) = 1609.

			a(1) = Prime(1) + Semiprime(1) + 3AlmostPrime(1) +
4AlmostPrime(1) + 5AlmostPrime(1) = 2 + 4 + 8 + 16 + 32 = 62.
a(6) = A114944(6) + A014614(6) = 112 + 112 = 224.

Harvey P. Dale, Table of n, a(n) for n = 1..3000

Cf. A000040, A001358, A014612, A014613, A014613, A114382, A114944.

Module[{nn=1000,p1,p2,p3,p4,p5,len},p1=Prime[Range[nn]];p2= Select[ Range[ nn], PrimeOmega[ #] ==2&];p3=Select[ Range[nn], PrimeOmega[ #]==3&];p4=Select[ Range[ nn],PrimeOmega[#]==4&];p5=Select[ Range[ nn], PrimeOmega[ #]==5&];len=Min[Length/@{p1,p2,p3,p4,p5}]; Total/@Thread[ {Take[ p1,len], Take[p2,len],Take[p3,len], Take[p4,len],Take[p5,len]}]] (* Harvey P. Dale, Apr 16 2015 *)

a(n) = A000040(n) + A001358(n) + A014612(n) + A014613(n) + A014614(n). a(n) = A114944(n) + A014614(n).

Corrected by Harvey P. Dale, Apr 16 2015

A114879 Numbers n coprime to 3 such that there exists an (n-1)-digit ternary number wherein each substring is indivisible by n.

Original entry on oeis.org

2, 4, 5, 10, 20, 37

Offset: 1

Don Reble, Feb 17 2006

a(7) > 64.

			20 is there because each substring of 1121212211122121211 (base 3) is indivisible by 20.

Cf. A114880, A114942, A114943, A114944, A114908, A114909, A114910, A114911, A114922.

cp's OEIS Frontend

A114966 Prime(n) + Semiprime(n) + 3AlmostPrime(n) + 4AlmostPrime(n) + 5AlmostPrime(n).

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

Mathematica

Formula

Extensions