A157496 -id:A157496 - cp's OEIS frontend

A159251 Composite numbers whose digit sum is a single-digit prime.

12, 14, 16, 20, 21, 25, 30, 32, 34, 50, 52, 70, 102, 104, 106, 110, 111, 115, 120, 122, 124, 133, 140, 142, 160, 200, 201, 203, 205, 210, 212, 214, 221, 230, 232, 250, 300, 302, 304, 320, 322, 340, 403, 410, 412, 430, 500, 502, 511, 520, 610, 700, 1001, 1002

Offset: 1

Parthasarathy Nambi, Apr 06 2009

Numbers of (2..6)-digit terms are 12, 40, 105, 260, 543. - Zak Seidov, Apr 12 2009

			250 is a composite number whose digit sum of 7 is a single-digit prime.

Cf. A002808 (composite numbers), A157496.

s={};Do[t=Total[IntegerDigits[n]];If[ !PrimeQ[n]&&(t-2)(t-3)(t-5)(t-7)== 0,AppendTo[s,n]],{n,7*10^3}];s (* Zak Seidov, Apr 12 2009 *)

Extended, minor edits and keywords easy, less added by Klaus Brockhaus, Apr 12 2009

More terms from Zak Seidov, Apr 12 2009

A157662 Composite numbers such that the last digit is equal to the sum of all the previous digits.

Original entry on oeis.org

112, 123, 134, 145, 156, 178, 189, 202, 213, 224, 235, 246, 268, 279, 303, 314, 325, 336, 358, 369, 404, 415, 426, 437, 448, 459, 505, 516, 527, 538, 549, 606, 628, 639, 707, 718, 729, 808, 819, 909, 1001, 1012, 1023

Offset: 1

Parthasarathy Nambi, Mar 04 2009

Numbers such as 11, 22, 33 are ignored.

			1023 is a composite number where the last digit is the sum of all the previous digits.

A002808, A157496, A157529

cp's OEIS Frontend

A159251 Composite numbers whose digit sum is a single-digit prime.

Views

Author

Keywords

Comments

Examples

Crossrefs

Programs

Mathematica

Extensions