A251605 Numbers k = concat(s,t) such that k = antisigma(s) + antisigma(t), where antisigma(x) = A024816(x).

226, 1046, 3881, 20206, 1970256, 57619059, 62109258

Offset: 1

Author

Paolo P. Lava, Feb 02 2015

Keywords

• nonn
• base
• more

Examples

			226 = concat(22,6); 22*23/2 - sigma(22) = 253 - 36 = 217; 6*7/2 - sigma(6) = 21 - 12 = 9. Finally 217 + 9 = 226.
		

Crossrefs

Cf. A000203, A024816, A253824, A253825.

Programs

Maple

with(numtheory): P:=proc(q) local s, t, k; global n; for n from 1 to q do for k from 1 to ilog10(n) do s:=n mod 10^k; t:=trunc(n/10^k); if s>0 then if s*(s+1)/2-sigma(s)+t*(t+1)/2-sigma(t)=n
then print(n); break; fi; fi; od; od; end: P(10^7);

Extensions

Incorrect term 240 removed by and a(6)-a(7) from Jinyuan Wang, Feb 16 2021