A179653 Triangular numbers (A000217) which are also primes in carryless digital root arithmetic in base 10 (A169911).

3, 6, 10, 15, 21, 28, 45, 55, 78, 91, 105, 136, 406, 496, 528, 595, 703, 741, 1035, 1081, 1225

Offset

1,1

Comments

The complement, triangular numbers (A000217) which are not primes in carryless digital root arithmetic in base 10 (A169911), begins {1, 36, 66, 153, 171, 190, 210, 231, 253, 276, 300, 325, 351, 378, 435, 465, ...}.

Links

Table of n, a(n) for n=1..21.

Index entries for sequences related to carryless arithmetic

Formula

A000217 INTERSECTION A169911.

Example

1, though triangular, is a unit, not a prime, in standard or carryless arithmetic.
36 is triangular, A000217(8), yet not in A169911 since in carryless digital root arithmetic in base 10 we have 3*15 = 36 where both 3 and 15 are primes, and 3*18=36.
Similarly, 66 is triangular, A000217(11), yet not in A169911.

Crossrefs

Cf. A000217, A169911,

Sequence in context: A025706 A025730 A066353 * A117520 A147846 A062099

Adjacent sequences: A179650 A179651 A179652 * A179654 A179655 A179656

Keyword

nonn,less,base,more

Author

Jonathan Vos Post, Jul 22 2010

Status

approved