A130596 Partial sums of skinny numbers (A061909).

1, 3, 6, 16, 27, 39, 52, 72, 93, 115, 145, 176, 276, 377, 479, 582, 692, 803, 915, 1028, 1148, 1269, 1391, 1521, 1721, 1922, 2124, 2334, 2545, 2757, 2977, 3198, 3498, 3799, 4109, 4420, 5420, 6421, 7423, 8426, 9436, 10447, 11459, 12472, 13492, 14513, 15535

Offset

1,2

Comments

The skinny partial sums of skinny numbers begin: a(1) = 1, a(2) = 3. The primes in the sequence begin: a(2) = 3, a(15) = 479, a(15) = 1721, a(38) = 6421, a(52) = 20899. The perfect powers in the sequence begin a(4) = 16 = 2^4, a(5) = 27 = 3^3, a(24) = 1521 = 39^2.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

a(36) = 4420 = 1+2+3+10+11+12+13+20+21+22+30+31+100+101+102+103+110+111+112+113+120+121+122+130+200+201+202+210+211+212+220+221+300+301+310+311

Mathematica

Accumulate[Select[Range[0, 1200], IntegerReverse[#^2]==IntegerReverse[#]^2&]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 02 2017 *)

Crossrefs

Sequence in context: A212977 A127935 A144538 * A280730 A339848 A321409

Adjacent sequences: A130593 A130594 A130595 * A130597 A130598 A130599

Keyword

base,easy,nonn

Author

Jonathan Vos Post, Jun 17 2007

Status

approved